UPDATE 9.30PM:

A lane on the eastbound carriageway of the M4 on the Prince of Wales Bridge has re-opened. 

Highways England have said investigations are almost complete at the scene, and clear-up has begun on debris.

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UPDATE 8.25PM:

The Prince of Wales Bridge remains closed due to ongoing police investigations and damange caused to the barriers.

Highways England have provided an update on Twitter on the incident which closed the Prince of Wales Bridge from just after 4.30pm.

The update is as follows:

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UPDATE 8.15PM:

The Prince of Wales Bridge is still closed in both directions.

Traffic cameras show the vehicles stranded on one carriageway of the bridge have began to be moved on.

South Wales Argus: Queues on the M4 Prince of Wales Bridge. Picture: Traffic Wales.Queues on the M4 Prince of Wales Bridge. Picture: Traffic Wales.

South Wales Argus reader Brooklyn Nightingale has been in touch with a video from earlier this evening, with a fire crew at Caldicot Fire Station leaving to attend the incident.

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UPDATE 6.50PM:

The accident which has closed the M4 Severn Bridge was a two-vehicle crash involving a van and a car. 

Emergency services  all attended the incident. 

A South Wales Fire and Rescue Service spokeswoman said: "We had a call at 4.36pm about a road traffic collision involving a van and a car. 

"Ambulance and police were on the scene. 

"[Fire] crews were involved in securing the vehicles and hydraulic cutters were used."

The fire service spokeswoman confirmed they had now left the scene.

South Wales Argus: The M4 Prince of Wales Bridge is closed in both directions. Picture: Traffic Wales.The M4 Prince of Wales Bridge is closed in both directions. Picture: Traffic Wales.

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BOTH carriageways on the Prince of Wales Bridge have been closed due to an accident.

Emergency services are at the scene, after the accident was reported just before 5pm.

As a result of the closure, traffic is building on either side of the motorway between Junction 22 for the M49 and J23 for the M48.

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The AA is reporting it is a "multi-vehicle accident" with delays of at least 15 minutes. A diversion is in place via the M48 Severn Bridge.

A Gwent Police spokesman said: "Emergency Services are dealing with a road traffic collision on The Prince of Wales Bridge.

South Wales Argus:

South Wales Argus:

Queuing traffic on the Prince of Wales Bridge. Picture: Traffic Wales.

"The bridge is closed and diversions in place.

"Apologies for any inconvenience."