GM Rides’ motoring expert urges travellers to check when they will reach the motorway, as disruption could affect journeys for late-morning and lunchtime flights
Passengers driving to Heathrow this October are being urged to check their journey carefully, with two planned “overnight” M25 closures continuing until 10am on Sunday mornings.
National Highways has confirmed that the M25 anticlockwise carriageway at junction 15, between the M4 slip roads, will close during the following periods:
Closure begins
Scheduled reopening
Saturday 17 October 2026, 8pm
Sunday 18 October 2026, 10am
Saturday 24 October 2026, 8pm
Sunday 25 October 2026, 10am
National Highways expects the M25/M4 interchange to be busiest between 8am and midday on those Sundays, with some delays potentially continuing after reopening. The clockwise carriageway and all connections between the M25 and M4 will remain open.
Majid Ismailzada, Marketing Director at GM Rides, says passengers should plan around their required terminal arrival time, rather than assuming a later flight means they will avoid the disruption.
“The word ‘overnight’ can make people think the work will be finished before their airport journey begins. The important question is what time you will reach that section of motorway.
A lunchtime flight can still mean travelling during the morning. Once you work backwards from check-in, security and the time needed to reach your terminal, your journey may fall much earlier than you first think.”
For example, a passenger with a noon departure who has been advised to arrive three hours beforehand would need to reach the airport at 9am, before allowing for the drive itself. Travellers should check the guidance for their particular flight and their airline’s check-in and bag-drop deadlines. Heathrow publishes its arrival guidance on its website.
Majid Ismailzada, Marketing Director at GM Rides adds:
“Start with the time you need to be at the terminal, then work backwards through the journey. If you are parking, include the transfer from the car park. If you are booking a car, give the operator your terminal and flight details so the collection time can be reviewed properly.
An extra half-hour might sound reassuring, but it is not a calculation. The allowance needs to reflect your route, when you are travelling and the conditions expected that morning.”
The impact will depend on the direction of travel and the terminal being used. Heathrow’s published driving directions route Terminals 2 and 3 via the M4 and junction 15 area, while Terminals 4 and 5 have access via M25 junction 14. Travellers should therefore check their exact terminal route rather than entering “Heathrow” as a general destination.
For traffic continuing anticlockwise through the closed section, the official diversion uses the M4 westbound to junction 5, turns back eastbound and rejoins the M25 anticlockwise at junction 4b.
Majid recommends checking the route when arranging the journey, again the day before travel and immediately before departure.
“Confirm the terminal, the collection time and the latest road information before you leave. If someone is giving you a lift, make sure they have checked the journey too.
“Drivers should follow the signed diversion and avoid making last-minute route changes while behind the wheel. If you need to review directions, ask a passenger to help or stop somewhere safe.”
The second closure also coincides with the end of British Summer Time. Clocks go back one hour at 2am on Sunday 25 October, so passengers arranging an overnight collection should confirm the date and local time with their driver.
Majid Ismailzada, Marketing Director at GM Rides says:
“For an overnight booking on the clock-change weekend, confirm the collection time directly with your operator, particularly if it falls within the repeated hour,” Majid says.
The aim is to agree a realistic plan before the day of travel, with enough time for the road journey and the airport requirements.”