From today vehicles over 7.5 tonnes will no longer be able to use the original crossing because the cables which support the bridge are deteriorating.

National Highways said safety was their “number one priority” and the weight restriction was to future-proof the bridge “for years to come”, but there are concerns the move will see more congestion on the Prince of Wales Bridge as well as other routes as HGV traffic has to use a 13-mile diversion back to the M4 Magor junction.

“It’s going to be a right mess, I am just dreading it,” said Darren Hobbs, transport manager for Jaga Brothers Tranport based in Magor.

“A lot of our work is time delivered – we are going to be ringing our customers to say, ‘sorry we can’t get there’,” he said, telling the BBC that the ban will create up to two hours extra work for drivers.

He said traffic in the area, particular on Friday was “carnage” and believes the changes will only make that worse.

According to National Highways, the UK government body which maintains the bridges, 32,000 vehicles used the M48 bridge a day in 2024. Of that figure 10% were over 7.5 tonnes, meaning an extra 3,270 large vehicles a day could have to find a different route.

National Highways said since tolls were removed on the bridge in 2018 there has been a 34% increase in traffic, which has meant a substantial increase in weight over the bridge which it was not designed for.

Confused.com car insurance expert Rhydian Jones said: “With HGVs being redirected to the M4 Severn Bridge instead, this is likely to have a huge knock-on effect for other road users, resulting in heavier traffic and delays on that popular route. The M4 is already one of the busiest links between Wales and England, used daily by commuters, airport travellers, and delivery drivers.

“With more large vehicles joining that route, drivers should plan for slower journeys, particularly during rush hour or busy travel periods.”

(Pic: The lorry-free Severn Bridge this morning, by Paul Hutton)