A man who witnessed the aftermath of a serious crash on the M2 claims part of the central crash barrier broke off after being struck by a car and hit a lorry travelling in the opposite direction trapping the driver.

Police have confirmed an investigation is under way into Thursday's multi-vehicle crash, which led to thousands of motorists being stuck in heavy traffic.

The accident between junction 5 (Sittingbourne) and 6 (Faversham) involved three cars and a lorry. The lorry driver suffered serious injuries and was airlifted to hospital after being cut free from his cab.

Daniel Heginbotham was at the front of the queue of traffic immediately after the crash.

The 42-year-old from Milton Keynes said: "A car travelling southbound hit the barrier at quite a shallow angle - but the barrier then spun across to the northbound carriageway and hit the lorry at cab level, trapping the driver."

Mr Heginbotham watched the whole rescue operation and has praised those at the scene.

He added: "The services on the scene were superb and a credit to their respective professions. They were calm and got on with the job - I absolutely take my hat off to them."

Police said they would not comment further as an investigation was under way.