People have been spotted playing football on the M4 after fuel protesters brought traffic to a standstill. The motorway was closed in both directions just after 8.30am.
Police have warned of "serious disruption throughout the day" as protesters target motorways in a demonstration over high fuel prices.
Delays are expected along parts of the M4 as protesters take action and call for a cut in fuel duty. The protest got off to a slow start, but my 8.30am the road traffic was brought to a halt and some motorists were even seeing playing a game of football on the opposite empty carriageway.
Read more: Live updates as protests set to cause disruption
Martin, who is trying to get to Cardiff from Portsmouth, told BBC Radio Wales at 8.30am: "I can see about seven white vans, quite a lot of protesters and a lot of police. Police look like they are trying to clear the road at the moment.
"The traffic is at a complete standstill in both directions. It looks like there is a few miles of traffic behind me. I am going towards Newport and we are at a complete standstill. It looks like the road is blocked in both directions. There are quite a few people who have got out of their vehicles to see what is happening."
Some motorists are out of their cars and some were spotted playing football, even though is illegal to do so.
Motorways are subject to specific traffic laws set out by The Motorways Traffic (England and Wales) Regulations 1982.
These make it illegal, for instance, to walk on a motorway, and govern where drivers are allowed to enter the roads, and how they must behave once they are on them.
Officers from both Gwent Police and Avon and Somerset Police are in attendance at the protest to ensure it is carried out in line with the law. Plans are also being made with emergency and critical services to reduce disruption, and Bristol Airport has issued a warning urging travellers to allow extra time if heading to or from the airport.
Protests across the UK will target mainly three-lane motorways and could see slow-downs on two lanes, leaving the fast lane free, according to FairFuelUK founder Howard Cox. While he said his organisation is not involved in the action, he is "fully supportive" of the demonstrations so long as they are conducted legally.
Chancellor Rishi Sunak has said he will carefully consider calls for a "more substantial" fuel duty cut after the 5p per litre reduction implemented in March failed to halt price rises.
Figures from data firm Experian show the average price of a litre of petrol at UK forecourts reached a new high of 191.4p on Thursday, while diesel rose to 199.1p. The Government said while it understands people are struggling with rising prices and have a right to protest, "people's day-to-day lives should not be disrupted" and warned that traffic delays "will only add to fuel use".
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