The dead man has been named as Howard Ieuan Harris, 39, from Pontypool.

Five men and three women were treated in hospital for their injuries but were all allowed to leave later.

The crash closed a section of the M4

The two lorries and four cars involved collided near tailbacks which had built up following an earlier accident involving a stolen Vauxhall Cavalier which had crashed into the central reservation at about 0420 GMT.

Tailbacks had formed after the motorway had been closed to allow the drivers of a van and lorry which had collided because of the Cavalier to move their vehicles.

Debris and stone chippings also had to be cleared from the carriageway.

The driver and any passengers of the Cavalier fled the scene before police arrived and officers are trying to trace them.

The westbound carriageway of the motorway between the Cardiff West slip road at junction 33 and the Miskin turn-off at junction 34 reopened after four hours of work to clear the scene of the accidents.

Ambulances were called to the scene just after 0530 GMT.

Police are appealing for witnesses to both collisions to contact them on 01656 655555.