Are Local Planning Authorities ready to monitor mandatory BNG? – by Richard Marsh MCIEEM & Dr Mikael Forup CEnv MCIEEM

Joint research by LPAs and tech firm Verna suggests urgent preparation is needed for the less obvious burdens of BNG – especially monitoring.

By Richard Marsh MCIEEM (Leeds City Council) and Dr Mikael Forup CEnv MCIEEM (Verna)

Mandatory Biodiversity Net Gain (BNG) is a transformational opportunity to reverse decades-long declines in our natural environment. It’s exciting: protecting and enhancing nature is why many of us chose our careers, and BNG brings a bigger role for ecology in the planning system.

But implementing BNG also creates a host of new requirements for Local Planning Authorities (LPAs), including collecting and scrutinising large amounts of data at planning application stage and over the following 30 years. LPAs are legally required to deliver this, when their planners and ecologists are already overstretched.

LPAs proving unable to manage their duties would endanger the entire BNG system. What role can new policies and processes, and new software systems, play in heading off this risk?

The authors are part of a group comprising seven LPAs and nature-focused software firm Verna, who have spent the last nine months exploring the challenges and potential solutions. Our research has also included interviews with a wider group of more than 35 ecologists working in local government.

Statutory monitoring duties are an underappreciated challenge

Our research has identified over 30 challenges for LPAs. Many of these are widely understood (if not yet solved). For example, the need to validate and assess the complex Biodiversity Metric for every relevant planning application.

However, we’ve found that not all colleagues across the country are aware of the scale of the new monitoring work – which is required to fulfil LPAs’ duties to assure the delivery of BNG within their geographical area.

Although more detail is needed from forthcoming secondary legislation and guidance, it is already clear that LPAs will have new responsibilities as the watchdogs of BNG.

The Environment Act 2021 strengthened the ‘Biodiversity Duty’ of LPAs to include requirements to enhance biodiversity and to report progress on BNG to central government. This Duty forms a core objective for LPAs and they are rightly trusted to deliver it (as long as appropriate support from Defra and Natural England is in place).

The Government has also indicated, in its latest consultation response on BNG, that it will task LPAs with ensuring BNG compliance using their existing planning enforcement powers.

Failure to deliver any of these responsibilities would jeopardise the benefits of BNG, and in some cases make LPAs vulnerable to legal challenge.

Dr Helen Markland MCIEEM, Principal Ecologist at Doncaster Council told us:

The true success of biodiversity net gain, and crucially its public perception and support, will hang on whether net gain projects deliver real ecological benefits. Local Planning Authority ecologists are going to have a pivotal role in overseeing the net gain process. Ultimately, it is ecological advice and scrutiny that is going to be critical to ensuring that the significant opportunities provided by biodiversity net gain are fully realised.

Monitoring requirements start in November and grow continuously

When BNG becomes mandatory in November, consent for every relevant application will include a planning condition requiring a BNG plan to be approved by the LPA prior to commencement of works. This plan must include detailed measures to enhance and/or create habitats over a 30-year period (potentially both onsite and offsite), with regular monitoring to ensure these actions are on-track.

The legal responsibilities for delivery are complex, and vary with the type of project and the bodies involved (potentially including landowners, developers, management firms, residents’ committees, and habitat bank operators).

In every situation the LPA has a watchdog role. In some cases this may be as simple as ensuring satisfactory legal agreements are in place at the outset and collecting reporting data over time. In a significant number of cases, however, the LPA will need or want to actively monitor the project over its 30-year lifespan.

What might this workload look like? To assure a project, the LPA should receive and scrutinise an ecological monitoring report on a defined schedule – typically this might be at years 1, 2, 5, 10, 20, and 30. Each and every project sets its own 30-year schedule going, so the total burden grows as more projects are consented. If an LPA consents 300 projects each year that need monitoring: after one year of BNG, checking these reports might require around eight weeks of staff time; after five years, this might have grown to 24 weeks per year – around 50% of a team member’s time. (These estimates assume that it takes just one hour to read and file or respond to each report.)

This is when everything goes smoothly. But there will inevitably be bumps along the way. To handle those, LPA teams may also need to:

  • Keep track of who is responsible for implementing BNG plans, including as land changes ownership or different bodies take over (possibly with implications for subsequent monitoring and enforcement approaches e.g. in the case of residents’ committees).
  • Check monitoring reports are submitted and chase missing ones.
  • Take action when plans go off-track, including negotiating remedial steps and ensuring relevant documentation is updated (such as the BNG plan and Biodiversity Metric), and using appropriate enforcement powers where necessary.
  • In some cases, undertake site visits to support all of these actions.

Teams will need to deliver all of this in a coordinated way across colleagues, recording and transferring all relevant data as staff members move on over a 30-year period.

Des Hobson MCIEEM, lead ecologist at Swindon Borough Council told us:

Properly monitoring BNG is vital to deliver our statutory duty and get the best outcomes locally, but it is a major undertaking that could easily tie up huge amounts of staff time – with knock-on implications for the planning system as a whole. Additional resources are needed but, with new staff almost impossible to recruit, we urgently need smart systems to help manage the workload.

New processes could help LPAs manage these duties

Our research has found that the solutions may lie partly in new policies and processes, and partly in smart software systems.

We have seen that some LPAs are getting policies and procedures ready now for the arrival of mandatory BNG.

For example, one of the authors is from Leeds City Council, which currently handles about 9,000 planning applications per year with a team of 1.8 full-time equivalent ecologists. From November a significant proportion of these applications will fall under mandatory BNG, and the Council is making thorough preparations.

The Council takes its Biodiversity Duty seriously, including in relation to BNG. It is now referring to itself as the ‘BNG Monitoring and Reporting Body’, and publishing details on how it will deliver all of the above duties including approving BNG plans, checking sites are entered onto the National Register, and monitoring and reporting on projects, as appropriate – including to the extent of site visits and enforcement action where necessary.

The Council considers that it has a duty to assure onsite and offsite delivery equally given that, after applying the appropriate multipliers, the Biodiversity Metric regards one onsite Biodiversity Unit as equivalent to one offsite Unit. However, onsite Units are likely to be more numerous (because they may be easier, cheaper, and less risky for developers to deliver), and are not subject to safeguards such as the National Register of offsite projects.

As a result, as well as developing policies and procedures to ensure that its costs to monitor and report on offsite delivery are understood and can be recovered, the Council is also considering whether Section 106 Agreements can be used for onsite delivery.

Leeds, like many LPAs, is also considering offering developers the option to buy offsite Units from the Council itself. This aligns with the Biodiversity Duty, and given that Councils are large organisations it is possible to avoid conflicts of interest with the right governance. For example separating delivery and assurance across teams, so that the same regime is applied to Council colleagues delivering BNG as is applied to third party offsite providers.

LPA ecologists are ideally placed to set up and deliver the BNG Monitoring and Reporting Body role, and in Leeds it is managed by the Nature team’s ecologists (sitting within Planning), who are able to assure delivery of BNG by other Council Land Management or Flood Risk Management services.

There is also a role for software to assist

Given the data burdens, software can also play an important role.

It is not possible to automate ecology, and human expertise will always be needed to interpret and make judgements on complex ecological information. For example, monitoring reports will usually need to be assessed by ecologists.

However, there are parts of the challenge where software is perfectly suited to assist ecologists (and our planning officer colleagues).

For example, smart software systems can:

  • Import and present the Biodiversity Metric via an easier interface, supporting initial assessment and long-term tracking of expected vs. delivered Biodiversity Units.
  • Check Habitat Management and Monitoring Plans are on file, keep track of updated versions, and help check that plans are based on good ecological science.
  • Keep track of what reports are due when, flag any that are overdue, and assist with prompting the responsible organisations to meet their obligations.
  • Highlight the most risky habitat enhancement or creation plans, to help prioritise human time. (This could enable an element of risk-based scrutiny, which may be inevitable given constrained resources.)
  • Provide a robust documentation trail when enforcement is required.
  • Calculate and report progress and Biodiversity Units delivered across all sites and projects – including in formats required by central government.

As well as saving LPA teams a great deal of time, having the right processes and software in place could help create confidence in the whole BNG system and reduce the need for active enforcement. If everyone knows LPAs are on top of things, everyone is more likely to proactively comply with their responsibilities.

We are creating solutions together

As a result of this collaborative research, new policies, processes, and tools are being created to provide support with monitoring – and all other parts of the BNG process.

For example, template BNG policies are being shared within the research group, and Verna is building a software tool (‘Mycelia’) to handle the data requirements.

To be most effective, these innovations need to be rolled out ahead of the start of mandatory BNG in November. The project team are happy to share them (the authors’ contact details are below), so that across the sector we can be as ready as possible for this new way of working.

We hope that by working together, we can avoid BNG becoming an unmanageable burden for LPAs and instead make it what it should be: an opportunity to create long-lasting nature-rich areas, help deliver wider benefits for our communities and environment, and in many cases generate revenue to support LPAs.

Richard Marsh is Senior Nature Conservation Officer at Leeds City Council, and a Member of CIEEM. He can be contacted on

Mikael Forup is Verna’s Director of Ecology, and a Member of CIEEM. He can be contacted on

Both authors are happy to share more about the project, including the policies and software being developed based on it.

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