Update 7pm:

Traffic has since returned to normal.

Update 5.34pm:

Traffic is now starting to ease.

Update 5.17pm:

Travel time remains at 75 minutes.

Update 5.10pm:

Newport Bus has tweeted: "**Customer Notice**Due to the A48 closure the 30 service will be diverted via the M4 motorway at Tredegar Park and off the motorway at Pentwyn, and the same diversion inbound. Sorry for the inconvenience caused. Thank you."

Update 5pm:

South Wales Argus:

The red lines shows congestion in Newport.

Update 4.48pm:

Travel time is 75 minutes.

Update 4.36pm:

There is queueing traffic for five miles.

Update 4.31pm: 

Congestion on the A48 Chepstow Road is now back to the B4245.

Update 4.30pm:

One of the lanes is partially blocked and queueing traffic due to accident.

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SEVERE delays can be expected following an accident.

The incident happened on the Coldra Roundabout.

Heavy traffic is being reported on Chepstow Road.

More to follow...