Highways Agency are planning to complete preparatory works at M25 Junction 15 ahead of the replacement of two bridge expansion joints starting in 2027.
To complete this work safely, the M25 junction 15 anticlockwise carriageway, above the M4, is scheduled to close overnight from 8pm Saturday 24 until 10am Sunday 25 October 2026
The M25 junction 15 clockwise carriageway, M4 eastbound and westbound carriageways, and all links between the M25 and M4 will remain open throughout the works.
Diversion route. https://www.google.com/maps/d/viewer?mid=12uSzjzs4G6N4pmFt4Dei-5s5xg-l870&ll=51.497570606189285%2C-0.5131658015441976&z=14
During both closures, anticlockwise traffic will need to exit the M25 at junction 15. A signed diversion route will be in place via the M4 to rejoin the M25 after the closure:
Follow the M4 westbound to junction 5
Turn around at M4 junction 5 (Langley Interchange)
Follow the M4 eastbound to rejoin the M25 anticlockwise via M4 junction 4b
Expecting the M25 and M4 interchange to be busier than usual on Sunday mornings. If you need to travel through the area, please allow additional time.
Further work will complete on weekday nights between 10pm and 6am. During weekday nights, a signed diversion route will be in place via M4 junction 4 and return. Diversion route map (Google Maps).
The bridge expansion joints that are being replaced have been in service for around 40 years. Work to replace them in 2027 will help maintain safe and reliable journeys for the 200,000 vehicles that use this section of the M25 each day for decades to come.
You can find information about this work and updates on the scheme webpage. (Link https://nationalhighways.co.uk/roads-and-travel/road-projects/south-east/m25-junction-15-m4-junction-4b-bridge-repairs-near-heathrow-airport/).. Please remember that closures can change at short notice. For the latest roadworks information, please visit www.nationalhighways.co.uk/travel-updates.