UPDATE: 3.06pm

The 21-year-old driver of the Peugeot involved in this morning's crash, who is from the Bristol area, has been reported for driving without due care and attention.

A man and a woman who were travelling in the Peugeot involved in this morning's crash and two women were travelling in the Fiesta were taken to the University of Wales Hospital in Cardiff. All four sustained minor injuries.

UPDATE: 12.22pm

The A48(M) westbound has re-opened and traffic is easing as this morning's accident is cleared.

UPDATE: 11.58am

Reader Ian Evans sent in this picture taken from the Castleton bridge.

South Wales Argus:

UPDATE: 11.22am

GWENT Police confirmed the collision happened at around 8.25am this morning and involved a Fiesta, a Peugeot and a van. Two people - a man and a woman - were travelling in the Peugeot and two women were travelling in the Fiesta.

All four have been taken to the University of Wales Hospital

The A48 Westbound between Junction 29 and the St Mellons junction remains closed at this time

If anyone has any information about the collision they are asked to call Gwent Police on 101 and quote log number 64 28/11/13

UPDATE: 10.06am

Congestion is reported on A48 Eastern Avenue to Pentwyn Road / Bryn Celyn Road. Emergency services are still attending the three-vehicle crash on the A48(M).

Both ways remain closed after the eastbound was closed to allow the Air Ambulance to land. The helicopter has left but there are no estimated re-opening times.

A diversion is in place via J30 (Cardiff Gate) and the A4232 Pentwyn Link Road between the A48 Eastern Avene (Pontprennau Junction) and the M4 J30 (Cardiff Gate). Traffic can also use the A470 from Gabalfa Interchange to M4 J32 (Coryton Interchange).

UPDATE: 8.48am

AN AIR ambulance is on route to a serious three car-pile up on the A48(M) this morning.

THE A48(M) is closed and queueing traffic is reported in both directions between M4 J29 and J29a, A48 (St Mellons) following the crash.

Gwent Police duty inspector Chris Haile has told drivers to avoid J29 westbound due to the collision.