Drivers are being warned over congestion ahead of what is expected to be the busiest late May bank holiday weekend on the roads since the start of the coronavirus pandemic.

Motoring services company the RAC predicted more than 20 million leisure trips by car will be made between Friday and bank holiday Monday.

That would be the most for the late May bank holiday weekend since 2019.

The worst day to travel is likely to be Friday, as the start of the long weekend coincides with the beginning of half-term for many schools.

Transport analytics company Inrix warned that journeys on the M25 clockwise between Junction 7 for the M23 and Junction 21 for the M1 are expected to be delayed by more than 90 minutes in the late afternoon on Friday.

Delays are anticipated to reach an hour on a 45-mile southbound stretch of the M5 – a popular holiday route – from Junction 16 north of Bristol to Junction 25 for Taunton, Somerset.

RAC spokesperson Alice Simpson said: “Our research suggests this weekend could be the busiest of the year so far on the roads, with millions of people embarking on getaway trips to make the most of the three days and, for those with school age children, the start of the half-term holiday.

“In fact, we’re looking at possible leisure traffic volumes returning to levels similar to what we last saw in 2019 before the coronavirus outbreak, as drivers’ desire to make the most of the UK increases.

“And, in those places where the warm spring sunshine makes its presence felt, the number of people deciding to get behind the wheel and head for the coast or countryside will only go up, swelling the overall volume of cars on the roads.”

Inrix transportation analyst Bob Pishue said: “With near-record number of travellers expected to be on the roads over the holiday period, drivers should be prepared for long delays, especially in and around major cities and towards the coasts.

“The best general advice to anyone spending time away from home this weekend is to travel as early or as late in the day as possible to avoid the worst delays.”

There will also be disruption to train services this weekend as Network Rail carries out engineering projects.

Services on the West Coast Main Line will be reduced due to work around Crewe and Carlisle.

Trains will also be affected by track renewals between Carstairs and Lanark in Scotland, while there will be significant changes to services on the Great Eastern Main Line because of work building a new station at Beaulieu Park to the east of Chelmsford.

Network Rail says it often carries out major engineering work over bank holiday periods to reduce the number of passengers impacted.