What happens if you buy a listed building with unauthorised works?

The council's powers

(2) A listed building enforcement notice shall specify the alleged contravention and require such steps as may be specified in the notice to be taken: (a) for restoring the building to its former state; or (b) if the authority consider that such restoration would not be reasonably practicable or would be undesirable, for executing such further works specified in the notice as they consider necessary to alleviate the effect of the works which were carried out without listed building consent; or (c) for bringing the building to the state in which it would have been if the terms and conditions of any listed building consent which has been granted for the works had been complied with.

• Who is served. The owner and the occupier, and anyone else with an interest materially affected (section 38(4)).
• When. At any time. Government guidance says there are no time limits for listed building enforcement notices, though the time that has passed may be relevant to whether the council considers a notice expedient (paragraph 057).
• If you do not comply. Whoever owns the building once the compliance period has ended is in breach and commits an offence (section 43(1) and (2)). It is a defence to show you did everything you could be expected to do, or that you were not served with the notice and did not know of it (section 43(4)). The council may also enter, do the work and recover its reasonable costs from the owner (section 42(1)).
• Recovering the cost. Expenses the owner incurs in complying are treated as incurred for the person who carried out the works (section 42(2)), which gives a route to claim them back from that person.
• Stopping work in progress. Since 25 April 2024 the council can issue a temporary stop notice, lasting up to 56 days, where it appears that unauthorised works are being carried out (section 44AA).

This differs from ordinary planning, where most unauthorised building work becomes immune after 4 or 10 years: see the 10-year enforcement rule. Listed building control has no equivalent.

A worked example

You buy a Grade II house in 2026. In 2015 a previous owner replaced the original timber sash windows on the front with uPVC casements, without listed building consent.

• The 2015 owner committed the offence under section 9. You did not.
• The council can still serve a listed building enforcement notice, on you as owner, requiring the timber sashes to be reinstated.
• If the notice is not complied with in time, you are in breach and commit an offence under section 43. The council could do the work and recover the cost from you.
• Your expenses in complying are treated as incurred for the 2015 owner (section 42(2)).

Regularising: consent after the event

(3) Where: (a) works for the demolition of a listed building or for its alteration or extension are executed without such consent; and (b) written consent is granted by the local planning authority or the Secretary of State for the retention of the works, the works are authorised from the grant of that consent.

So you can apply for listed building consent to keep works already done, and the application is judged like any other: by their effect on the building's special interest. Two limits matter:

1. The consent looks forward only. The works are "authorised from the grant of that consent", not from when they were done. Government enforcement guidance puts it as consent being "not granted retrospectively".
2. A certificate is not an option. A certificate of lawfulness of proposed works under section 26H is available only for works not yet carried out.

If consent for retention is refused, the alternative is to reverse the works, with consent where the reinstatement itself affects the building's character. If a notice is served, one ground of appeal is that listed building consent ought to be granted for the works (section 39(1)(e)). The appeal must reach the Planning Inspectorate before the date the notice takes effect, which is at least 28 days after the notice is served (sections 38(4) and 39(2)).

What to check before you exchange

1. The list entry. On the National Heritage List for England, note the grade and the date of listing. Works carried out before the building was listed did not need consent. Listing covers the interior and pre-1948 structures in the curtilage unless the entry says otherwise.
2. The council's records. A local search answers the Law Society's CON29 enquiries on listed building consents (enquiry 1.1) and on listed building enforcement notices, served or proposed (enquiry 3.9). Read each consent, its approved drawings and its conditions. See how to read a planning history.
3. The building against the consents. Walk the house with the drawings. Compare windows, doors, internal walls, fireplaces, floors, roof coverings, render and paint, kitchens and bathrooms, and any extensions. See listed building consent for how the test falls element by element.
4. The seller's account. Ask in writing what was done, when, by whom, and with what consent. Dates matter most for planning immunity; for listed building control they matter mainly for whether the work predates listing.
5. Building Regulations. Approvals and completion certificates are a separate question in the same local search.

Where something is unconsented, you can ask the seller to regularise it before exchange, or agree how the cost of consent or reinstatement is reflected in the price.