The Easter hop could leave travellers in a holiday hell

Experts have warned of chaos on the transport networks as millions try to make the most of the blue skies.

This weekend is tipped to be the warmest so far this year, with temperatures expected to soar to 20c (68f) on both days.

Eighteen million cars are expected to hit the road from lunchtime tomorrow - twice the normal number - as officer workers finish early for the break.

They face major roadworks at 44 locations and a catalogue of station closures which will put even more pressure on routes.

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Queues: Chaos is expected at airports including Heathrow, above

A spokesman for the RAC said: "We are predicting a 100per cent increase in traffic, journeys are going to be up to 60 per cent longer than normal with traffic building from about 3pm.

"For the rest of the weekend congestion will be more staggered, but if the weather is sunny then it's inevitable that certain routes will be even busier."

Getaway routes affected will include the M25, particularly around Heathrow, M1 northbound, M4 westbound, M6 through the West Midlands and north of Manchester and Liverpool, M5 northbound in the Midlands and southbound around Bristol.

The AA warned that a full holiday football programme, as well as events including the British Superbike Championship at Brands Hatch in Kent would pile even more pressure on roads.

On the railways, major engineering work beginning on Friday means passengers travelling to parts of Hampshire and the south coast will have to use buses.

Work on the West Coast Mainline will affect hundreds of passengers travelling through the Midlands.

Those heading abroad for the break are expected to face similar hassles. The Association of British Travel agents estimates 2.5 million Britons will spend Easter overseas.

More than 1.1million of them - an average of 191,000 passengers a day - will pass through Heathrow between tomorrow and Tuesday.

Six hundred thousand are expected to travel through Gatwick and 450,000 through Stansted.

Favourite destinations include New York, Tenerife and Turkey, and many are taking shorter trips to Dublin and Rome.

Last night a spokesman for BAA, which runs seven UK airports, admitted that the Easter getaway will be "challenging".

For many passengers, it will be the first time they have flown since heightened security measures were introduced last summer - not to mention the new baggage limits introduced by British Airways.

Travel advisers have been drafted in for "queue combing", trying to ensure passengers know what they can and can't carry on board the plane, the spokesman said.

Eurostar has also laid on extra trains in preparation for a rush of passengers travelling to France.

A Met Office spokesman said that the forecast sunny spell is due to a band of pressure building up over Britain, coupled with warm air arriving from the Continent.

Temperatures are expected to climb as the week progresses, the spokesman said.

"It's possible that by the weekend we might see the warmest weather of the year," he said.

"It should be a good Easter for most parts of the country."