More than seven million drivers are expected to take to the roads this weekend, with journeys taking an average two and a half hours longer than usual, travellers have been told.
Those heading abroad could face airport delays of an average of one hour 45 minutes, while rail passengers could be held up for 30 minutes, a survey by the internet insurance company esure.com found.
Based on Bank Holiday statistics from May 2005, the research showed that about 1.9 million other travellers will go by plane and about 900,000 by train. As many as 73 per cent of people will be staying at home however, with a third of them making the choice to avoid delays.
The travel news organisation Trafficmaster warned that drivers could expect congestion hotspots on most major motorways. There would be jams on most parts of the M25, on the M1 northbound from the Home Counties to Yorkshire and on stretches of the M5 and M6, it said.
Network Rail said there would be no closures on mainline routes on Monday, although there will be engineering work on parts of the west coast and east coast routes tomorrow and Sunday.
Passengers heading for the sun this weekend had no reason to fear a repetition of a computer breakdown which caused widespread disruption to flights on Wednesday, the National Air Traffic Services (Nats) said. However, last night the company had yet to establish the reason for the electronic glitch at its West Drayton centre near Heathrow.
A spokesman for Nats said all "unusual inputs" into the system had been ring-fenced and would not be repeated until the cause of the collapse had been identified. The spokesman said that the backlog of flights had been cleared by yesterday morning.
The Association of British Travel Agents said that today and tomorrow would be the busiest days for those heading abroad, with 400,000 flying from Heathrow airport, 250,000 from Gatwick, 150,000 from Stansted and 64,000 from Luton. Nearly 400,000 will leave through regional airports, including 140,000 from Manchester, 12,000 from Southampton and 31,000 from Nottingham East Midlands. Although this weekend is not a bank holiday in Scotland, nearly 65,000 Scots will also be leaving the country.
Meanwhile British holidaymakers in Florida were preparing for hurricane-force winds and torrential rain as Tropical Storm Katrina gained strength yesterday on its approach to the US. British tour operators, who have thousands of clients in Florida, were keeping in touch with the American National Hurricane Centre. The state has already been hit by Tropical Storm Cindy and Hurricane Dennis.