Introduction

Biodiversity Net Gain (“BNG”) seeks to create and improve the natural environment of the nation by requiring that all new development has a positive impact (‘net gain’) on biodiversity.

This is not mere policy. By statute, most planning permissions[1] are now deemed to have been granted subject to the statutory biodiversity gain condition. 

The statutory biodiversity net gain condition requires development to achieve at least a 10% increase in biodiversity value relative to the pre-development diversity value of the onsite habitat. The 10% increase can be achieved in one of three ways

• through onsite biodiversity gains eg improvements to the development site itself;
• [if this cannot be achieved] through registered offsite biodiversity gains eg improvements to a different site (for instance creation of [a park], which may have nothing to do with the development site itself
• By purchasing statutory biodiversity credits.

The statutory condition requires only that a Biodiversity Gain Plan (“BGP”) is produced and submitted for approval. But the condition also requires that development may not begin until the plan is approved; in that sense, it is, by statute, a pre-commencement condition. A gain is only to be counted if the LPA is satisfied that it will be maintained for 30 years following completion of the development.

Guidance encourages LPAs not to include the statutory condition in the list of conditions in the permission. However, information about the condition is to be included in informatives, and there is model wording for this. In addition, in order to approve the BGP, the LPA must be satisfied that the gains will be achieved and maintained and that whatever requirements are included in the BGP are actually carried out. For that reason, LPAs may decide to include enabling and monitoring conditions and/or s106 agreements; there are template conditions available.

Separately, LPAs are required by the Natural Environment and Rural Communities (NERC) Act to monitor and report on the extent to which BNGs are achieved in practice.

This article looks at the challenges created for planning and planning enforcement teams arising from these requirements.

What does the guidance say?

Paragraph 7 in the PPG on BNG says

“How will biodiversity net gain be effectively monitored and enforced?

Failure to comply with the biodiversity gain condition by commencing development without approval of the Biodiversity Gain Plan will be a breach of planning control. Local planning authorities have a range of planning enforcement powers and have responsibility for taking whatever enforcement action may be necessary, in the public interest, in their area.

Effective enforcement is important to tackle breaches of planning control and maintain integrity of the decision making process. Local planning authorities are already encouraged to prepare local enforcement plans, and set out the priorities for enforcement action, and they may want to update these to reflect the introduction of biodiversity net gain. This could cover both the initial delivery and ongoing management and maintenance mechanisms to assist monitoring of gains in the longer term.

Appropriately worded planning conditions and planning obligations would also help achieve effective monitoring and enforcement of biodiversity net gain, particularly in relation to the maintenance and monitoring of significant onsite habitat enhancements and registered offsite biodiversity gains. [our emphasis in bold]

Is proactive monitoring and enforcement required then?

There are arguably two approaches to the BNG condition. The first is for LPAs to take the view that the condition only requires that a biodiversity plan is prepared and approved. Implementation is not statutory, neither is monitoring. As part of approval, the LPA must be satisfied that the plan will be implemented and maintained; the LPA could take the view that this can be assumed unless there is something that makes it unlikely (eg access or land condition makes it impossible).

The second approach would be for the LPA to introduce various additional conditions to ensure that the plan is implemented and maintained. 

The guidance clearly points to the second approach. But in following the guidance, the LPA creates something of a rod for its own back. If a condition is thought important enough to impose, there is arguably an expectation that it will be monitored and, if necessary, enforced.

Separately, LPAs are required by the Natural Environment and Rural Communities (NERC) Act to monitor and report on the extent to which BNGs are achieved in practice. It seems unlikely that this could be achieved without some form of overall monitoring, though it does not require monitoring in any individual case.

The reference in the guidance to including monitoring and enforcement in enforcement plans could suggest that it is to be a planning enforcement function. This is probably to read too much into the guidance. It seems more likely that those drafting the requirements saw BNG monitoring more in line with other monitoring currently undertaken by council planning teams, for example s106 monitoring, housing delivery. Reporting is at strategic level. Proactive monitoring is reserved for large developments (some will have a s106 monitoring officer), and otherwise more haphazard. Enforcement on a reactive basis when complaints are made.

Nevertheless, the guidance says what it says and LPAs will need to take a view on whether to introduce some form of proactive monitoring.

Is proactive monitoring by a planning enforcement team realistic?

With some exceptions, notably County Councils with waste and minerals monitoring functions, planning enforcement has not, traditionally, been a proactive service. This is for several reasons

• The focus on expediency is built into planning enforcement legislation. As a rule, it is not expedient to take enforcement action against development which has not generated complaints.
• Case law makes clear that the purpose of enforcement is remedial. In many cases, the enforcement task is simply to ensure that development is given proper scrutiny in a planning application.
• Almost all development is in breach of planning control to some extent. There are often minor deviations from plans, failure to comply with minor parts of the GPDO etc. The scale of the task were the service to be proactive would be immense and resources simply do not allow for such monitoring.
• Planning enforcement already suffers from a “jobsworth” image and proactive enforcement in the absence of complaints would only worsen that image. There is little political will/budget for proactive planning enforcement.

A requirement for proactive monitoring of the statutory BNG condition by a reactive enforcement service would therefore require significant change. A better option might be to develop procedures for monitoring and reporting within planning teams, in the same way as happens with, for example, construction management plans, leaving enforcement to situations where there is a clear failure. In any case, LPAs need to determine what monitoring they are going to do and who is going to do it. The guidance approach, that it is “for enforcement” is not adequate.

What changes would be required?

Key areas of interest for LPAs to monitor would be to ensure that

• development is not commenced without a BGP
• the BGP is implemented
• the BGP is maintained for 30 years

Commencement of development

The statutory condition requires that it is satisfied before development is commenced. As a rule, neither planning nor planning enforcement teams routinely monitor commencements. The new LURA duty to notify commencement applies only to certain development and is not yet in force. If notification of commencement is conditioned, it may not be observed. Even if a development is commenced, it is not necessarily implemented. If it departs materially from plans, what is commenced is not the permission but rather a different development. 

Planning enforcement teams do not routinely maintain even a list of all permissions. Why would they? Many permissions are granted with no expectation of being built out; they create fall backs, they are alternatives or they are created to increase land value.

Monitoring permissions without commencement notices is impracticable and pointless. Monitoring sites to see whether they have commenced without a BGP is similarly impracticable. The best that it is likely to be possible is to monitor commencement notices and ensure that they are matched to a BGP approval.

Implementation of the BGP

If the LPA imposes a condition that the BGP must be implemented in accordance with its terms, it would need to monitor that. BGPs will be created by ecologists and confirmation of compliance is likely to require ecologist input. This is not really a function which currently exists within local authority planning teams. Not only is a very significant budget needed were it to be introduced but it is not clear that there are sufficient trained staff to undertake it. There are alternative approaches which could be written into s106 agreements, such as requiring sign off from the applicant’s own ecologist or dumbing down the BGP to such an extent that it can be easily measured (eg number of bat boxes) but these would need to be written into the agreement or plan at the outset. 

Maintenance

In order to count an improvement as a gain, the LPA must be satisfied that it will be maintained for 30 years after completion. Completion is described in the guidance. It is not the same as “substantial completion” as used for immunity purposes. Practically, it should be defined in the BGP itself.

Clearly, checking maintenance of BGP measures for 30 years is entirely impracticable. It is unnecessary anyway; a new permission within the 30 years would carry another BNG condition. A better approach would be to ensure that the BGP itself or the s106 agreement contains maintenance measures. This would require a careful approach to approval of BGPs, something which is, again more of a planning matter than an enforcement one. 

Protecting against BNG breaches

BNG can be delivered on site, with improvements to the site itself, or off-site, with improvements to another site. The third method, BNG credits is outside the scope of this article. The mechanisms for protecting against BNG breaches are slightly different for on and off-site delivery of BNG in that planning conditions can only be used for on-site delivery, but s106 agreements can be used for both on- and off-site delivery. There is no scope to include a condition relating to a site which is not within the redline. 

On-site BNG delivery

If the LPA decides to introduce additional monitoring and reporting provisions of on-site BNG, it can do so by condition or by s106 agreement. A typical condition or agreement might include provisions for

• Notifying commencement of the development
• Creation of a Habitat Management and Monitoring Plan (“HMMP”) to support the BGP plan
• Certification of implementation of the initial requirements of the BGP plan.
• Submission of regular monitoring reports during the 30 year period in line with the methodology and frequency specified in the approved HMMP.

Whatever condition or s106 agreement is used must be carefully considered to ensure that

• Enough information is supplied to the LPA to support its own reporting and monitoring obligations (eg under NERC or a Local Plan).
• Its responsibility to check implementation and maintenance of the BGP is kept manageable.

Where on-site net gain is secured by means of a s106 agreement, monitoring fees can to some extent compensate for the resource impact of monitoring. But where the on-site gain is secured by means of a planning condition, there is no mechanism by means of which the LPA can charge for its monitoring costs. Even where monitoring costs can be recovered by means of the s106 agreement, anticipating and calculating the LPA’s costs for 30 years of monitoring is “finger in the air” at best. Whatever provision is used, LPAs should consider including provisions for recouping the costs of formal action for non-compliance.

LPAs also need to consider how such agreements will survive sale of the land by the developer and/or disappearance of the developer. The provisions need to be drafted such that they fall onto subsequent landowners. Particular care may be necessary where a management association is proposed given legislation around rights to acquire freeholds.

There are different enforcement challenges for enforcing conditions v s106 agreements and we look at these below.

Off-site BNG delivery

As mentioned, there is no scope to condition the off-site delivery of BNG. Land used for off-site BNG delivery should therefore be secured for the length of the BGP, either by means of a s106 agreement or a conservation covenant. A conservation covenant is a private voluntary legal agreement between a Responsible Body and a landowner which establishes than land will be used for a conservation purpose.

If off-site delivery is secured by means of a s106 agreement, it is for the LPA to enforce, whereas if the off-site delivery is secured by means of a conservation covenant, it is for the Responsible Body to enforce.

Either approach could include monitoring and enforcement costs. 

The Responsible Body approach is arguably easier for the LPA as monitoring and enforcement are outsourced. It remains to be seen whether sufficient schemes exist and whether they deliver the net gains sought by the legislation.

Enforcing against BNG breaches

When the standard approach to enforcement (is there development, is it in breach, is it immune?) is applied to BNG, it is clear that there are a number of major uncertainties. We look at these now.

What is the breach?

The statutory BNG condition operates as a pre-commencement condition. Development may not commence until a plan is produced and approved. As a rule, failure to comply with a pre-commencement permission means that the entire development is without permission. However, this only applies where the condition “goes to the heart” of the permission.

It is not clear whether the BNG condition will go to the heart of the permission. On the one hand, if the BNG is important enough to be given statutory backing, arguably it must be considered fundamental. On the other, if the actual measures in the BGP are minor, can its preparation really be fundamental?

Where no plan has been produced at all, or where it has been produced but not approved, the first problem for enforcement is therefore identifying the breach. Without case law to guide us, it seems likely that enforcement notices in the alternative (development without permission and in breach of condition) will be required.

Issues may arise with timing. For example, a BGP may be produced in time but not approved within 3 years of the permission. In this case, arguably the Whitley[2] exception will apply and the permission will be ‘implemented’. Again, notices in the alternative may be an appropriate approach.

Where a plan has been produced and approved but not implemented, the position is clearer. Assuming proper implementation of the remainder of the permission, the breach would be a breach of condition, and either a BCEN or BCN would be appropriate.

Where the LPA has imposed additional implementation, information and monitoring conditions, then, again assuming proper implementation of the rest of the permission, the breach is likely to be a breach of condition unless there is something in the condition that operates as a true pre-commencement condition.

Immunity

The nature of the breach (see above) will determine the immunity period. Alternative notices may therefore carry alternative immunity periods. Where the breach is failure to produce a plan, immunity runs from substantial completion of the development if the statutory condition is a true pre-commencement condition such that the whole development is without permission. But it runs from the start of development if the permission is implemented but there is a breach of condition.

Similarly, where the breach is a breach of an implementation, information or monitoring condition included in a permission, the breach runs from the first failure to comply. 

There could be some confusion arising from whether a maintenance condition is breached, given that the 30 year period runs from “completion”, giving rise to whether there has been completion. 

Expediency

Enforcement of the statutory condition will be subject to the same expediency test as any other enforcement notice. There is, of course, no formal expediency test for a BCN but there would be no scope for a BCN if, as noted above, the statutory condition is a true pre-commencement condition.

The guidance says that LPAs have a “responsibility for taking whatever enforcement action may be necessary, in the public interest”. This does not absolve them of considering expediency but the guidance becomes a factor in the expediency consideration. There is, of course, general “public interest” in the upholding of the system so, to that extent, this guidance is nothing new. 

The big problem with expediency is that the BNG condition does not (yet[3]) apply to deemed permissions under s177 TCPA 1990 ie on ground (a) appeals.

Taking enforcement action opens the door (in most cases) to a ground (a) appeal under which there is no statutory requirement to produce a BGP. It is difficult to see why it would be expedient to take enforcement action on the failure to produce a BGP when the effect of that action is to disapply the requirement.

That said, the NPPF guidance requiring BNG still applies and appellants will be required to demonstrate the net gain. Even if the statutory condition does not apply, presumably inspectors will consider whether BNG is met in deciding whether to uphold the ground (a) appeal and impose conditions to secure it if necessary.

Enforcement notice or BCN?

The breach (see above) will determine the available enforcement options. Where there is a choice, the usual considerations will apply in terms of the advantages and disadvantages of each. But there are additional considerations specific to BNG. 

Enforcement notice against the whole development

As mentioned above, if the statutory BNG condition operates as a true pre-commencement condition, it will render the entire development in breach of planning control. The remedy for a breach of planning control consisting of operational development is usually removal of the entire development. If more than three years have passed since the permission, the permission may no longer be extant to form an alternative means of remedy under s173(4) or an obvious alternative. 

This is not a problem that is exclusive to BNG. It is fair to say that neither the courts nor inspectors are fond of finding that conditions are true pre-commencement conditions. But the status of the BNG condition as a statutory creation puts it in a special class of condition. Should a house be removed because of failure to provide a BGP involving a few bat boxes? There is likely to be considerable pushback against attempts to enforce against whole developments for BNG failures. As mentioned above, notices in the alternative would be a sensible approach.

Breach of Condition Notice (“BCN”)

This is intended to be a quick remedy whereby a notice is issued to require the developer or controller of the land to comply with a condition. There is no right of appeal against such a notice, but it can be judicially reviewed. Non-compliance with a Breach of Condition Notice is a criminal offence subject to an unlimited fine on summary conviction (in England).

In principle a BCN is a good remedy for breaches of implementation, information and monitoring conditions. There is no requirement to consider expediency and the BCN offers a quick resolution.

There are, however, some potential problems. 

• The first is that the BCN route is only as good as the permission. If the permission has fallen away (whether because it was not implemented or because the BCN condition is truly pre-commencement) there is no condition to breach.
• Similarly, it is only as good as the condition. If the condition does not require implementation of the BGP by a certain date or it does not require continuous maintenance, or if it only requires an HMPP which turns out to be toothless, then there may be no breach.
• While conditions run with the land, BCNs do not. Where land ownership changes after the BCN, the LPA would need to serve new notice.
• Because there is no right of appeal, there is no option to correct or amend a condition on appeal.

Enforcement Notice for Breach of a condition

An Enforcement Notice may be issued for failure to comply with any condition or limitation subject to which planning permission has been granted. This would include the statutory BNG condition which is deemed into the permission. It would also include implementation, information and monitoring conditions which the LPA decides to include in the permission. 

The Enforcement Notice is subject to a right of appeal to the Secretary of State. Non-compliance with an Enforcement Notice is a criminal offence subject to an unlimited fine.

The benefits of an Enforcement Notice are its right of appeal which allows a variation of a condition if a deemed planning application is made; and that the Enforcement Notice runs with the land so it binds future owners.

The problems include that it is dependent on the permission and the condition, as with the BCN. And that there is a right to appeal which means that the process takes longer to achieve results.

Enforcement of S106 agreements

S106 agreements are usually prepared alongside the grant of planning permission. At the risk of labouring the point, if the statutory condition is a true pre-commencement condition, the permission is not implemented. The s106 agreement is not then enforceable.

Otherwise, where the breach is a breach of condition, enforcing the s106 agreement is an option. S106 agreements be enforced in the following ways.

Seek an Injunction from the courts

Securing an injunction is the nuclear option. It is expensive and time consuming. Although it would be appropriate for the types of breaches where BNG has not been delivered at all, it probably would not appropriate be for minor slippages.  

Where the reasons for non-compliance are financial, i.e. the landowner cannot afford to maintain BNG on the land, it is difficult to see how BNG will be achievable, even by means of injunction.

Direct action

It may be possible to take direct action by entering the land and carrying out the operations required by the s106 agreement and recover the costs of doing so. Such action might achieve the BNG aims, but the costs may not be recoverable from the landowner as the land might not have sufficient value.

Civil contractual litigation

Litigation is a cumbersome, expensive process which might not achieve the results of securing BNG.

Who does the enforcement?

S106 agreements are usually negotiated by the LPA legal team who take instructions from the development management team. Once the agreement is completed, it is usually filed away in both teams’ records and, with the exception of planning permissions on major schemes, are usually forgotten about. It is extremely rare for planning enforcement teams to ever get involved in breaches of s106 agreements. Although some LPAs have s106 monitoring officers to actively monitor compliance with s106 agreements, not all LPAs have that luxury.

This may lead to a two-tier system where planning enforcement teams are involved in enforcement of BNG secured by condition but not secured by s106 agreements. 

Conclusion

LPAs need to consider how best to approach ensuring the implementation and monitoring of BNG. The approach of including implementation, information and monitoring conditions is one approach but it is arguably “gold plating” which creates its own problems for LPAs.

Where such conditions or s106 agreements are used, they need careful drafting to ensure enforceability and cost recovery.

Proactive monitoring is fairly unrealistic. It is entirely unrealistic to expect it of reactive planning enforcement functions. The conditions/s106 agreements need to draft for this. Planning enforcement functions must be alive to the risk of unrealistic expectations.

The enforcement of the statutory BNG condition is made very difficult by a lack of clarity as to whether it is a true pre-commencement condition and the very complex case law surrounding commencement and implementation of permissions. Complex enforcement notices in the alternative may be required.

The enforcement of implementation, information and monitoring conditions depends on the quality of their wording. Toothless conditions simply referencing BGP and HMPP plans are often not enforceable.

As with much in planning, the aim of BNG is laudable but there is a need for pragmatism in its execution. 

Sources and websites for further reading:

Planning Practice Guidance on BNG

Guidance on Reporting your Biodiversity duty actions

PAS BNG Legal agreement and planning condition templates

[1] There are a number of exemptions for householder development, biodiversity “gain sites”, small scale self-build and custom housebuilding, deemed permissions under s90 and de minimis exemptions. These are set out in reg 4 of The Biodiversity Gain Requirements (Exemptions) Regulations 2024.

[2] Whitley v Secretary of State for Wales (1992) 64 P&CR 296

[3] Purposes for which BNG has come into effect is currently only for planning applications in part 3 of the TCPA 1990 but presumably this will change in future