Establish what has been approved
Search the planning register for decisions, approved drawings, conditions and relevant later applications. A neighbour may be relying on permitted development, or the work may differ from an approval in a way the council needs to examine. Report the factual difference you can identify rather than assuming that all building without a recent application is unlawful. [1][2]
If the issue is an unapproved use, describe what is occurring and when it began, distinguishing direct observations from assumptions. The authority may need information to establish the nature and history of a suspected breach. [1]
Send a specific report
Use the enforcement reporting route for the council covering the site. Provide the address, a description of the alleged breach, relevant application references, dates where known and the harm you believe results. Richmond's reporting guidance is one local example: it asks for the alleged contravention, its location, the harm and what could overcome that harm. [3]
Photographs or dated observations can help explain the report, but collect them lawfully without entering neighbouring land. Do not present an estimate of height or distance as a measured fact unless it has actually been measured reliably. The aim is to give the investigating officer usable information. [3][1]
Check the authority's approach to confidentiality rather than assuming every council accepts anonymous reports. Richmond, for example, says anonymous complaints will not normally be pursued and explains that evidence may be needed in formal proceedings. Those are local arrangements, not a guarantee of anonymity across London. [3]
What the council may do
The authority may investigate, request information, seek a retrospective application or consider formal enforcement. It can also conclude that there is no breach or that formal action is not expedient. Government guidance emphasises proportionality and the planning harm involved. [1]
Submitting a complaint does not itself stop construction. Where urgent intervention may be warranted, describe the specific concern clearly; the council decides which statutory powers, if any, are appropriate. Do not promise yourself a particular outcome or resolution date. [1][3]
The enforcement time limits changed
For operational development substantially completed on or after 25 April 2024, the usual enforcement period is 10 years. The change also applies to unauthorised changes to a single dwellinghouse occurring on or after that date. The previous four-year periods remain relevant to qualifying earlier cases; other breaches generally have a ten-year period. Exceptions, including concealment and further enforcement action, can affect the position. [1]
These are not party wall deadlines or a reason to delay reporting a current concern. Whether particular work has become lawful requires its own factual and legal assessment. [1][4]
Use separate routes for separate problems
Missing party wall notices, damage and disputed boundaries are not cured by a planning enforcement complaint. Deal with those matters through the relevant surveyor or legal route, and raise safety concerns through the appropriate safety or building-control channel rather than waiting for a planning decision. [4]