The accident, said to involve six cars, happened on the clockwise carriageway near junction 13 for Staines-upon-Thames and Wraysbury in Surrey. Three lanes of five are closed as emergency services deal with the smash, it is believed.

       Queues are back to junction 10 - the A3 link - for Cobham, Surrey. It is estimated the travel time between the two junctions is around 40 minutes at this stage.

       The crash happened just south of Heathrow Airport, My London says, so motorists heading for the airport should leave with plenty of time to complete their journey.

       There is no diversion in place but drivers can leave at junction 11 and take local roads through Chertsey and Egham Hythe to rejoin the motorway at the Staines-upon-Thames junction.

       These roads are congested as a result though.

       The latest INRIX update states: "Long delays, lane closed and queueing traffic for 11 miles due to accident, six cars involved on M25 clockwise after J13 A30 Staines By Pass (Staines).

       "Congestion to J10 A3 ( Wisley Interchange). Travel time is 35 to 40 minutes.

       "Lanes two, three and four (of four) are closed adjacent to the entry slip road. Vehicles are using the entry slip to pass the scene."

       Anti-clockwise traffic is congested from junction 14 for Heathrow Airport and Stanwell Moor due to onlookers. Drivers should continue on the motorway though, as there's no need to seek alternative routes through Syanwell Moor or Wraysbury.