Nearly 300 people could face fines after they were caught ignoring red ‘X’ signs on the motorway.

Two lanes were closed on the anti-clockwise carriageway of the M25 approaching j20 for Kings Langley/A41 because of a diesel spillage, on Thursday.

The slip road was shut, as was lane 1 and drivers were ordered by the gantry signs above to only be in lanes 3 and 4.

Road policing officers were parked up in a lay-by near the closure to check that drivers were obeying the signs but they quickly realised they weren’t and the unit said it caught nearly 300 disobedient motorists in just one hour.

Letters will be sent to the registered owners of the vehicles after the officer wrote down each offending vehicle’s number plate.

The BCH Road Policing Unit says the owners will be asked to confirm who was driving and will then be dealt with accordingly.

The unit says an officer’s evidence is “sufficient enough” even if the disobedience was not caught on camera.

Drivers were stuck in tailbacks that stretched back to j22 for London Colney for most of the afternoon.