The ‘overnight’ closures on the M25 end on two Sunday mornings, which may affect journeys for late-morning and noon flights at Heathrow.
Travellers are urged to check when they reach the M25 and plan ahead.
| 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.
More Information on The Impact
The clockwise carriageway and all connections between the M25 and M4 will remain open.
The impact will depend on the direction of travel and the terminal being used.
National Highways has confirmed that the M25 anticlockwise carriageway at junction 15, between the M4 slip roads, will close during the following periods:
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.
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.
Travellers Urged to Plan
Planning ahead means starting with the time you need to be at the terminal, and work backwards.
Travellers should check their exact terminal route rather than entering “Heathrow” as a general destination to avoid unnecessary delays.
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.”
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.
For example, passengers for a flight at 12pm may be advised to be there 3 hours early. Travellers should plan to reach the terminal at 9am, and anticipate changes on their journey because of the closures.
It is not advisable to make last minute changes. Start planning early, keeping in mind the road journey, check-in, and security.
For arrival guidance, visit Heathrow’s website.
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 if booking with a driver.
Read more about the M25 closures here. Works are subject to change.
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Written by Ejemen.
