From National Highways website

Cobham Road bridge repairs over M25

We’re maintaining the bridge carrying Cobham Road over the M25 between Cobham and Leatherhead in Surrey.

• Weekend closure – Friday 19 December to Monday 22 December 2025
• essential maintenance on Cobham Road bridge over M25 between Cobham and Leatherhead. Some work was completed in June 2025.
• To keep the bridge safe, we’re:
  • renewing the waterproofing layer to prevent rainwater damage to the bridge, replacing the expansion joints at both ends of the bridge which have reached the end of their serviceable life, addressing a surface depression in the carriageway which is apparent on the north embankment of the bridge, and a void in the revetment below drainage maintenance, and resurfacing the carriageway and refresh the road markings for smoother journeys 

  Closures

• Close the bridge which carries Cobham Road over the M25, between Cobham and Leatherhead, from 9pm Friday 19 December until 6am Monday 22 December 2025 for urgent repairs. 
• We’re resurfacing the road to fix a defect and restore the 40mph speed limit. The speed limit is currently 30mph following a safety inspection.
• Diversions
• when the Cobham Road bridge is closed, directly above the M25, there will be fully signed diversion routes via Leatherhead. Southbound traffic (from the Cobham direction), will be diverted onto:
  • the A245 Woodlands LaneWoodlands RoadRandalls Road eastboundBull Hill southboundStation Road westboundB2122 Waterway RoadGuildford Road southboundCobham Road westbound

  Northbound traffic (from the Fetcham direction), will be diverted onto:

  • Cobham Road eastboundthe B2122 Guildford RoadWaterway Road northboundA245 Station Road westboundStation Approach northboundRandalls RoadWoodlands RoadWoodlands Lane westbound

  Diversion route mapPlease note that there is a railway bridge along our diversion route with a 3.7 metre (12’-3”) height restriction.This bridge is located on Cobham Road between Shamrock Close and River Lane in Fetcham.Drivers of high-sided vehicles are encouraged to plan ahead and seek alternative routes if necessary. Acce

• ss to all nearby properties and businesses on both sides of the Cobham Road bridge will remain available, however, it won’t be possible to drive across the bridge during the works.We’ll need to close the bridge over a weekend again in 2026 to replace the second bridge expansion joint. We will provide more details closer to the time.Please remember that closures can change at short notice. You can check the latest information on our daily closures page or find live travel information on our Traffic England. Our travel alerts give details of live incidents on our network.