Millions of people are expected to embark on summer getaways this weekend as experts warn of ‘severe delays’ on what is expected to be the busiest weekend of the year.

Motorists have been told they could face a “weekend of woe”, with motoring group RAC predicting the second busiest summer weekend since 2015.

A total of 3.6 million car journeys are expected on Saturday, with another 2.9 million trips on Sunday, as the bank holiday weekend gets underway.

The RAC said the weekend – including trips taken on Friday – would be second only to 2022, during the hot summer that followed two years of coronavirus lockdowns.

RAC Breakdown spokesperson Alice Simpson said: “With the end of the school holidays fast approaching it seems day trips will be the main cause of traffic this weekend, so for many drivers it could be a case of ‘day trip delays’.”

The breakdown service added it was expecting the M5 to be “one of the worst roads for delays in the country”, specifically southbound between J15 and J23, as well as northbound between J25 and J15 on Monday with returning traffic.

The motorway had more than 30 miles of tailbacks between Bristol and Taunton, Somerset, earlier.

A National Highways spokesperson said the “severe delays” of more than an hour were due to “the sheer volume of traffic”.

The Port of Dover said it was also expecting its busiest weekend, with 11,000 tourist cars over the course of Saturday.

A spokesperson for the port said it was “free-flowing” on Saturday morning and reported wait times of just five minutes at border control.

Brittany Ferries – which operates between the UK, France and Spain – said most overnight sailings were now full this weekend, but there was still space on daytime trips.

Travel association Abta estimated more than two million Britons would head overseas this weekend, covering the period between Friday and Sunday.

London Luton Airport expects 220,000 passengers to pass through between Friday and Monday, with a total of 2.5 million passengers expected over the school summer holiday period.

Clare Armstrong, head of guest experience at London Luton Airport, said Paris is “clearly leading the way for city break destinations”.

She said the last week had seen a 25% rise in people travelling to the French capital and that was “no doubt” due to the Olympic Games.

Amsterdam, Athens, Barcelona and Lisbon are also very popular, she added.

Meanwhile, Heathrow Airport is anticipating its “busiest ever summer” and will serve 250,000 passengers a day at its peak.

Storm Lilian, which swept in on Friday, has also worsened delays. Fallen trees blocked several rail lines in Wales, western England, the West Midlands and northwest England– including on the key West Coast main line between Stafford and Crewe and between Macclesfield and Stockport. Many trains between Manchester city centre and the airport are cancelled or delayed. The intercity link between Birmingham and Bristol is also blocked by a fallen tree.

Commuters in the London area face long delays due to a broken-down train on the Thameslink north-south line through the city centre.

Over the weekend three key intercity lines to and from London will be hit by closures and diversions due to Network Rail projects. Engineers will be working on both the East and West Coast main lines, as well as the Great Western route through the Severn Tunnel.