Police have warned drivers there will be “serious disruption throughout the day” due to demonstrations on motorways over high fuel prices.
There are road closures across the country due to demonstrations on the M62 and M180 in Yorkshire and Lincolnshire and the M4 and M5 in Wales and the South West.
It is understood protests will mainly hit three-lane motorways and see slow-downs on two lanes, leaving the fast lane free.
Roadblocks have brought parts of the M4 to a standstill this morning. Campaigners focused their demonstration on a section of motorway between Bristol and South Wales.
There is slow-moving traffic both ways across the M4 Severn Bridge, a main route between Wales and England.
For a few minutes this morning, both carriageways of the M4 approaching the Severn crossing were brought to a standstill by go-slow protests travelling east and west.
Protests have also resulted in a slow-moving traffic on the M5 near Exeter heading northbound.
FairFuelUK founder Howard Cox said his organisation is not involved in the action but he is “fully supportive” of the demonstrations so long as they are conducted legally.
He said : “I totally support their protest because people have reached the end of their tethers at the moment.”
Why are the protests taking place?
Protesters are calling for a cut in fuel duty and have been organised on the Fuel Price Stand Against Tax Facebook group.
It comes as 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”.
How the M4 Severn Bridge will be affected
Gwent Police said protests will take place on the road network between 7am and 7pm today.
They said organisers had indicated an intention to block the bridge, which crosses the River Severn, with the protest starting on the M4 at Magor services, junction 23A eastbound, and junction 20 of the M4 westbound.
Bridge repair works are affecting the M48 bridge, another main route that crosses the river, meaning crossing the Severn is likely to much more difficult than usual.
The protesters plan to close two lanes on the eastbound and westbound carriageways of the M4 bridge between 7am and 7pm.