If you're flying out of Heathrow on a Sunday in October and planning to drive, it's worth checking your route first. National Highways is closing stretches of the M25 overnight on two Sundays in the month, and the warning is aimed squarely at airport passengers who might otherwise assume the motorway around Heathrow runs as normal.
The closures fall on two October Sundays and apply overnight, with diversions signposted for through traffic. The work is part of the long-running upgrade of the M25 between junctions 10 and 11, the stretch that skirts Heathrow itself — one of the busiest sections of motorway in the country, carrying a heavy share of the airport's arriving and departing traffic alongside everyday commuters. Crews use the quieter overnight hours to lift beams, resurface lanes and carry out works that can't be done safely with traffic running, which is why the road disappears completely from the map for a few hours rather than just narrowing to a single lane.
For travellers, the practical impact depends on timing. Early-morning departures are the risky ones: a flight at 6am or 7am means driving in exactly the window when closures are still in place, and a diversion around the Heathrow stretch can add anything from 20 minutes to over an hour depending on how traffic copes. Daytime and afternoon travellers are unlikely to notice much, since the motorway is due to reopen before the morning rush builds.
There are sensible workarounds. Check National Highways' road closure alerts before you set off, build in extra time if your flight leaves before mid-morning, and consider routing via the A30 or A312 into Heathrow directly if the motorway diversion pushes you in the wrong direction. Public transport is another obvious hedge — the Elizabeth line, Piccadilly line, Heathrow Express from Paddington and various coach services all bypass the motorway entirely, and they keep running through the night.
If you're being dropped off or picked up by someone who drives in from outside London, share the closure details with them in advance so the driver isn't improvising at midnight on a diversion sign. Taxi and private-hire firms in the area generally know the works schedule, but if you've booked a fixed-price airport transfer, flag it when you book so the operator plans the right route.
Who this matters for: anyone driving to or from Heathrow on the affected Sundays, especially pre-dawn departures or very late arrivals. It's a small planning tweak, but missing a long-haul flight because of a motorway closure is an expensive way to learn about roadworks.
