Dangerous structures notices and the planning aftermath

A dangerous structures notice is served under the Building Act 1984, not the planning legislation, and that separation causes most of the trouble that follows. Building control can require or carry out demolition in the interests of safety under section 78 within hours. Planning control then asks, weeks later, why a building was demolished without permission. The statutory defences that bridge the gap are narrow, and they depend almost entirely on evidence gathered at the time.

So the single most useful thing an owner can do when a dangerous structure is identified is to document the position before anything is taken down. A structural engineer's written opinion, dated photographs and a note of what was considered and rejected are what turn a demolition into a defensible emergency rather than an unauthorised act.

What a dangerous structures notice does

Under section 77 of the Building Act 1984 the local authority applies to the magistrates' court for an order requiring the owner to carry out works or to demolish the building. Under section 78 the authority may take emergency measures itself where immediate action is needed, notifying the owner where that is reasonably practicable, and recover its expenses afterwards.

In inner London the regime differs. The dangerous structures provisions of the London Building Acts legislation apply, administered by the district surveyor, with a faster procedure and a long-established practice.

Either way the function is safety, exercised by a building control or regulatory team that is not thinking about planning. The notice will not tell you whether demolition needs planning permission, and the officer serving it is not obliged to.

Emergency works and the planning position

Demolition of a building is development. Permitted development rights in Part 11 of Schedule 2 to the General Permitted Development Order 2015 cover much ordinary demolition, subject to prior approval of the method of demolition and the restoration of the site.

That prior approval requirement falls away where the demolition is urgently necessary in the interests of safety or health, provided written justification is given to the local planning authority as soon as reasonably practicable. Note the condition attached to the exception. The justification is not optional, and leaving it until the council asks is the error that converts an emergency into an enforcement file.

Conservation areas and listed buildings sit outside Part 11 altogether, which is where the real exposure lies.

Where demolition has already happened

For an unlisted building in a conservation area, demolition without planning permission is a criminal offence under section 196D of the Town and Country Planning Act 1990. The statutory defence has four limbs, and all of them must be satisfied.

1. The works were urgently necessary in the interests of safety or health
2. It was not practicable to secure safety or health by works of repair or by works affording temporary support or shelter
3. The works carried out were the minimum measures immediately necessary
4. Notice in writing justifying the works was given to the local planning authority as soon as reasonably practicable

Limb two is where most defences fail. Propping, shoring, fencing and temporary roofing are usually available, and a contractor's advice that demolition was quicker or more economic does not meet the test. Limb three catches over-demolition: taking down a whole building when the dangerous element was a gable or a chimney stack.

A near-identical defence applies to works to a listed building carried out urgently in the interests of safety or health under section 9(3) of the Planning (Listed Buildings and Conservation Areas) Act 1990. The structural evidence that supports it is the same material discussed in structural surveys for a scheme relying on retention.

Listed buildings and emergency works

Two further mechanisms are worth knowing because they often appear in the same file.

A local planning authority may execute urgent works for the preservation of an unoccupied listed building, or the unoccupied part of one, under section 54 of the Listed Buildings Act, and recover the cost from the owner. An owner who has let a building deteriorate may therefore receive a bill rather than a notice.

The authority may also serve a building preservation notice on an unlisted building it considers to be of special interest and at risk, which brings listed building protection into effect immediately for a limited period while listing is considered. Owners who announce demolition plans for an interesting unlisted building sometimes trigger exactly that response.

Reinstatement expectations

Where demolition has taken place unlawfully in a conservation area or to a listed building, reinstatement is a real possibility rather than a theoretical one. An enforcement notice can require steps to remedy the breach, and in demolition cases that can mean rebuilding.

Inspectors have required reconstruction where significant unlawfully demolished fabric could be replicated, and such decisions are indicative of how the issue is approached rather than binding on any later case. The practical consequence is that salvage matters. Materials carefully taken down, labelled and stored support a reinstatement scheme; materials sent to a skip remove the option.

Prosecution and enforcement run in parallel. A successful defence to the criminal charge does not prevent the council taking enforcement action in relation to the planning breach, and vice versa.

Evidence to keep at the time

Assemble this while the scaffolding is still up, because it cannot be recreated afterwards.

• A structural engineer's written report describing the defect, the risk and the options considered, dated and signed
• Photographs and video of the defect from multiple positions, with dates, including close-ups of the failure
• A measured survey or a photographic record of the building before works, to the recognised recording levels where the building has heritage interest
• Written record of why repair, propping or temporary support was rejected, with any quotations or advice obtained
• Correspondence with building control and the planning authority, including the written justification sent under the exception
• A salvage schedule listing materials retained, with storage location
• Records of any highway licence, hoarding permission or street occupation obtained

Where heritage interest exists, a Historic Building Recording to the appropriate level is the recognised format for that record. Councils usually expect a suitably qualified author and professional review is strongly advised. Street occupation during emergency works has its own consents, set out in scaffold licences and highway occupation.

Regularising the position afterwards

Take the planning position in hand early rather than waiting for the council to open a case.

Apply retrospectively where the demolition or works needed permission. A retrospective application is available for development already carried out, and for a listed building it is possible to seek consent for works already executed, though doing so does not remove any criminal liability that has arisen. Say so plainly to your client rather than implying the application cures everything.

Write the application around the four limbs of the defence even where no prosecution has started, because the same facts answer the planning question. A Structural Survey establishing the condition before works, and a Heritage Statement assessing what was lost and what can be reinstated, are the two documents the case officer will read first.

An illustrative example. A rear wing of a Victorian commercial building in a conservation area develops a bulge after a drain failure. The owner obtains an engineer's report within 24 hours recommending immediate removal of the upper storey as the minimum measure, props the remainder, photographs everything, salvages and stores the brickwork and parapet stone, and writes to the planning authority the same week with the engineer's report attached. The retrospective application for the remaining works, with a reinstatement scheme using the salvaged material, was determined without enforcement action.

That outcome came from the paperwork, not from the demolition decision. The decision was the same one a less careful owner would have made.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.