Second Severn Crossing was closed for hours after hay lorry fire

South Wales Fire and Rescue Service was called to the scene at 12.47pm and firefighters remain on scene.

Motorists are asked to use the M48 to cross into Wales.

There are delays of about 10 minutes to get through the toll booths. 

UPDATE: 1.50pm

The crossing is closed both ways but more firefighters are en route to deal with the lorry blaze. 

Currently there are four appliances there - two from Avon and Somerset, one from Maindee and another from Caldicot. 

UPDATE: 2.12pm

Motorists queueing for the tolls are slowly being let through onto the M4.

According to Traffic Wales, the delays are likely to last until 4pm to 4.15pm westbound before they are fully cleared. Delays are expected to last another hour on the eastbound stretch. 

M4 update. Diversions in place and traffic stuck at the tolls is being let through slowly. pic.twitter.com/JF7xTvEEcx

— NPAS Filton (@NPAS_Filton) January 24, 2016

UPDATE: 2.34pm

The delays are now likely to last until 4.45pm to 5pm westbound, according to Traffic Wales. 

UPDATE: 2.45pm

Gwent Police will reassess whether the M4 can reopen at 3.15pm and said the motorway has been closed “on safety grounds”, according to a statement.

UPDATE: 3pm 

South Wales Fire and Rescue Service do not appear optimistic about the upcoming assessment and disruption is set to continue. 

Update on Second Severn Crossing, incident will be ongoing for a further 1-2 hours BE

— SW Fire & Rescue (@SWFireandRescue) January 24, 2016

UPDATE: 3.33pm

The M4 is now open eastbound over the Second Severn Crossing. 

#M4 : Now open : Eastbound : J23 Rogiet

— South Wales (@TrafficWalesS) January 24, 2016

UPDATE: 3.55pm

A South Wales Fire and Rescue Service spokeswoman said the police are anticipated to reopen the westbound carriageway - but with speed warnings in place. 

UPDATE: 4.04pm 

A video shows smoke billowing from the lorry earlier this afternoon. 

Video from lorry fire on M4 1 of 2. pic.twitter.com/uQ8Ej6i9Ja

— NPAS Filton (@NPAS_Filton) January 24, 2016

Video 2 of 2. pic.twitter.com/bKkXLsKu0y

— NPAS Filton (@NPAS_Filton) January 24, 2016 

UPDATE: 5.18pm

According to Traffic Wales, the M4 westbound is is "expected to be clear" between 7.45pm and 8pm. 

UPDATE 6.07pm 

That time estimate has been revised to 8.30pm to 8.45pm by Traffic Wales.

UPDATE: 6.45pm

The motorway has now reopened, according to Highways England:

#M4 W/B J22 - J23 now open. Toll booth restrictions, queues on approach whilst trailer recovered from earlier fire. pic.twitter.com/NXNuUUJXR9

— Highways England (@HighwaysSWEST) January 24, 2016

Were you stuck in the traffic? Send your tweets to @southwalesargus, email us on newsdesk@southwalesargus.co.uk or call 01633 777246.