Drivers preparing to hit the roads this Bank Holiday weekend are being warned to expect the worst traffic in three years.
According to RAC research, 13 million leisure trips are due to be taken by car between today and Monday, making this the busiest May Day bank holiday on the roads since 2016.
The bulk of the congestion is expected to happen today, with drivers aiming to make the most of the long weekend by beginning a total of 4.4 million leisure trips as early as possible.
The worst of the queuing is likely to happen between 4pm and 7pm, and drivers are being urged to avoid travelling between those hours where possible.
RAC spokesman Rod Dennis said: "Despite it looking like the weather will take an usually cold turn for the start of May - certainly after the recent Easter heatwave - our figures suggest drivers are still keen to make the most of the long weekend, with significantly more saying they are planning a leisure trip by car this year than in recent years.
"However, there is a risk that drivers will suffer their own 'motoring mayday' if they are not careful, since the colder nights we're about to experience could be enough to cause some older car batteries to finally give up the ghost.
"Luckily, temperatures will rise during the day and it isn't due to be a washout.”
He added: "The advice is again to try to use the roads when they are quieter, which primarily means avoiding Friday afternoon and evening if possible, and setting off earlier on Saturday, especially if travelling any great distance."
Anyone considering train travel as an alternative transport option may be disappointed - parts of Britain's railways will shut down for the second time in three weeks this weekend as major engineering work is carried out.
No trains will run to or from London Euston between Saturday and Monday while work in preparation for HS2 is carried out.
Network Rail warned this will have a "major impact on journeys" as alternatives routes will take longer and be busier than usual.
Virgin Trains, which operates services from London Euston on the West Coast Main Line, is urging passengers to "avoid travelling on these dates unless you absolutely have to".
Other engineering work taking place over the weekend includes track renewal work in the South West and upgrading of overhead wiring in Essex.
Network Rail says it aims to carry out major projects over bank holidays because fewer passengers use the railway during those periods.