How long do neighbours have to object to a planning application?

When a valid application is received, the council publicises it — typically letters to adjoining properties, a site notice, and in some cases a press notice. The statutory consultation runs for 21 days from that publicity.

Late comments aren't automatically ignored. Most authorities accept representations up to the point the decision is issued, and officers generally read whatever is on file when they write their report. But nothing obliges them to wait, so a comment on day 40 of an 8-week determination is a gamble.

For prior approval applications — such as larger rear extensions — the neighbour consultation is built into the process: adjoining owners get 21 days, and only if they object does the council assess the impact on amenity.

If you're the applicant, this window is why the early weeks matter: objections tend to arrive in that first month, and knowing what's been said gives you time to respond with amendments before the officer forms a view.

If you're the neighbour, don't sit on the deadline. A concise, material objection submitted inside the 21 days carries its full weight; a late one relies on goodwill and timing.