M40 traffic: Multi-vehicle crash forces motorway to close 'for several hours' with long delays near Heathrow

WATCH: Motorway crackdown on dangerous drivers

SOUTH YORKSHIRE POLICE
Felix Reeves

By Felix Reeves


Published: 12/07/2025

- 08:58

Updated: 12/07/2025

- 09:42

Thames Valley Police are conducting an investigation following the crash

Drivers continue to face long delays on a key motorway after a serious collision involving multiple vehicles in Buckinghamshire.

The M40 northbound in Buckinghamshire is closed between J1a Denham Interchange (Watford (M1), Rickmansworth, Heathrow Airport, Slough (M4),(M11, M23) M25) and J2 Beaconsfield Interchange (Beaconsfield, Amersham, Slough A355; Beaconsfield Services).


National Highways reports that a serious collision occurred on the approach to Junction 2 and involved several vehicles.

The accident prompted Thames Valley Police, Buckinghamshire Fire and Rescue, South Central Ambulance Service and National Highways to send teams to the scene.

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Large parts of the M40 remain closed this morning

Large parts of the M40 remain closed this morning

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Traffic maps from National Highways show long delays along the M40, with closed roads, while stationary traffic can be seen to the east of the J1a entry slip.

The incident was first reported at around 1.30am this morning, with National Highways: East providing updates on the situation via social media.

At 5.30am, the transport organisation reported that the road is expected to remain closed until at least 8am, although they warned it could be longer.

Traffic on the M40

Drivers are dealing with long delays along the M40

NATIONAL HIGHWAYS

In the most recent update, it said: "The #M40 northbound between J1a (#M25) to J2 (#Beaconsfield) remains CLOSED for a police investigation following a multi-vehicle collision.

"The road is expected to be closed for several further hours."

The road issue could cause havoc for motorists attempting to access London Heathrow Airport, especially as Britons look to make use of the warm weather.

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National Highways stated that motorists should allow for extra journey time if the closure impacts their planned route.

Drivers are being advised to plan ahead and potentially even "re-route or even delay your journey".

National Highways has outlined a diversion route for motorists to follow after the multi-vehicle collision.

Large parts of the M40 remain closed this morning

National Highways said they expected the M40 to remain closed for several hours

NATIONAL HIGHWAYS

Drivers are advised to follow the route marked with a hollow triangle symbol on local road signs

  • Traffic should join the M40 eastbound
  • Exit at J1 Denham Roundabout
  • At the roundabout, take the first exit onto the A40
  • Follow the A40 Oxford Road through Gerrards Cross
  • At the Pyebush Roundabout, take the first exit onto the A435
  • At the Beaconsfield Interchange roundabout (M40 J2), take the third exit to join the M40 northbound