Who decides whether a major project needs mitigation?

Local planning authorities and the Mayor (for strategic cases) decide, using the London Plan, local plans and EIA thresholds; NSIPs follow Planning Inspectorate procedures.

How can I report a breach of mitigation commitments?

Report to the borough planning enforcement team with evidence and dates; for NSIP compliance contact the Planning Inspectorate for the relevant DCO case.

Are there standard mitigation forms?

There is no single London-wide mitigation form; mitigation appears within Environmental Statements, planning conditions, and DCO obligations—check borough and Planning Inspectorate guidance for templates.

London Planning Law: Major Project Mitigation

Environmental Protection England 4 Minutes Read · published February 02, 2026

Introduction

In London, England, major project mitigation plans are governed by a mix of city-level strategic policy, borough planning powers and national infrastructure rules. This guide explains how mitigation is considered in decisions, who enforces requirements, the typical sanctions and the application and appeal pathways for large developments in London.

How decisions are made

Major projects affecting London are reviewed under the London Plan for strategic policy, local borough plans for site-specific controls, and—where applicable—the national Nationally Significant Infrastructure Project (NSIP) regime and Environmental Impact Assessment (EIA) rules.

The Mayor of London sets strategic planning policy that boroughs and applicants must follow when preparing mitigation measures for climate, air quality, noise, transport and biodiversity; borough planning authorities apply the London Plan within local decision-making processes London Plan^[1].

Key elements of mitigation plans

Baseline assessment: EIA or equivalent environmental assessments identifying receptors and impacts.
Design mitigation: embedding measures in plans, drawings and specifications.
Management and monitoring: monitoring schedules, triggers for adaptive measures.
Timetables and deadlines for implementation tied to planning conditions or DCO obligations.

Applicants should document mitigation in a dedicated section of the planning statement or DCO application.

Consultation and statutory consultees

Mitigation proposals must be consulted with statutory consultees such as the Environment Agency, Historic England and Transport for London where relevant; NSIP applications follow the Planning Inspectorate notification and consultation process Planning Inspectorate^[2].

Penalties & Enforcement

Enforcement for failure to implement agreed mitigation may be taken by the local planning authority, the Mayor (for strategic cases), or via national enforcement for NSIPs; specific monetary penalties and escalation depend on the controlling instrument and court outcomes.

Fine amounts: not specified on the cited page for London policy and strategic guidance; see cited legislation and national procedures for statutory penalties and criminal sanctions Town and Country Planning / EIA regulations^[3].

Escalation and repeat offences: the cited strategic and national pages do not list specific escalation bands or per-day figures; enforcement typically progresses from compliance notices and planning conditions to enforcement notices, stop notices, injunctions and prosecution where necessary, subject to statutory processes and court discretion.

Non-monetary sanctions and remedies commonly used:

Enforcement notices and requirements to restore land or remove unauthorised works.
Injunctions or court orders to compel compliance.
Works carried out by the authority with costs recovered where permitted.
Suspension or conditions on future permissions in some cases.

If enforcement is contemplated, consult the relevant borough planning enforcement team promptly.

Enforcers and complaint pathways:

Local borough planning enforcement teams (responsible for day-to-day enforcement of planning conditions and mitigation).
The Greater London Authority/Mayor for strategic matters and responses to referrals under the London Plan London Plan^[1].
The Planning Inspectorate for NSIP compliance and post-decision requirements Planning Inspectorate^[2].

Appeals and review routes:

Appeal to the Planning Inspectorate against certain enforcement notices or refusal of planning permission (times and routes depend on the notice type).
Judicial review is available for legal errors in decision-making; time limits are strict—seek legal advice; specific statutory appeal time limits are not specified on the cited strategy pages and must be checked on the relevant notice or statutory instrument.

Applications & Forms

Major infrastructure projects use Development Consent Order (DCO) applications or standard planning applications with supporting mitigation documentation. The Planning Inspectorate provides application guidance and relevant application forms and procedural guidance for NSIPs Planning Inspectorate^[2]. Fee schedules and exact form titles or numbers are not specified on the cited London strategy pages; check the Planning Inspectorate and relevant borough planning pages for current forms and fees.

For major projects, publish mitigation monitoring commitments in a single Monitoring and Management Plan accessible to the public.

Action steps for applicants and affected parties

Prepare a clear mitigation section in the Environmental Statement or planning statement and tie measures to enforceable conditions.
Engage statutory consultees early and document responses.
If you suspect non-compliance, report to the borough planning enforcement team and provide evidence, photos and dates.
If enforcement action is issued, note appeal deadlines on the notice and seek legal advice promptly.

FAQ

Who decides whether a major project needs mitigation?: Local planning authorities and the Mayor (for strategic cases) decide, using the London Plan, local plans and EIA thresholds; NSIPs follow Planning Inspectorate procedures.
How can I report a breach of mitigation commitments?: Report to the borough planning enforcement team with evidence and dates; for NSIP compliance contact the Planning Inspectorate for the relevant DCO case.
Are there standard mitigation forms?: There is no single London-wide mitigation form; mitigation appears within Environmental Statements, planning conditions, and DCO obligations—check borough and Planning Inspectorate guidance for templates.

How-To

Identify whether the project is a local planning application or an NSIP and check the applicable guidance.
Commission an Environmental Statement or equivalent baseline assessment addressing air, noise, biodiversity and transport.
Draft mitigation measures clearly tied to design drawings, specifications and monitoring triggers.
Submit mitigation documentation with the planning or DCO application and consult statutory consultees.
If permission includes conditions or obligations, implement monitoring and submit compliance reports as required; respond promptly to enforcement notices.

Key Takeaways

Mitigation must be enforceable: link measures to conditions or obligations.
Early consultation with statutory consultees reduces later enforcement risk.
NSIPs follow separate national procedures; use the Planning Inspectorate guidance for DCO applications.