A young man is in a critical condition in hospital following a multi-vehicle crash.

The accident occurred at around 8 o'clock last night on the M4 at Moyvalley when a car travelling towards Dublin hit the barrier.

A second car went to the assistance of the crashed vehicle when a third car collided with the second car.

A 21 year old man - understood to be the driver of the second car - was taken to Blanchardstown hospital where his condition is described as serious.