"Do come down, it will be a wonderful day," he said, as he visited the south-west to inspect Britain's biggest ever traffic management operation, which swung into action on Friday.

"It is a great event and we are organised to deal with it."

However, he warned people not to make a last-minute decision to head for the region. "It is a little late," he said.

"People will have to spread the times when they come here, make sure they book somewhere to stay, and take some food and water in case they run into congestion."

The BBC's Jane O'Brien: "At the traffic news centre, it's quieter than usual"

Mr Prescott toured the nerve-centre of the traffic operation in Exeter, designed to cope with an estimated 1.5m people flooding into Cornwall ahead of Wednesday's event.

It is monitoring traffic from 60 "traffic spy" cameras covering the main routes from Bristol to Cornwall, and putting live pictures and other information on the Internet.

On call: The centre will relay information to a Website

This will then be accessed by the traffic management team, including Devon and Cornwall police, local county councils, and the Highways Agency.

Military drafted in

Mr Prescott, who is also Minister for the Environment, Transport and the Regions, also opened seven miles of the new A30 between Ottery St Mary and Exeter - completed six months ahead of schedule especially for the eclipse.

The rest of the controversial £50m dual carriageway, which has been the focus of protest by anti-road activists, will be finished next spring.

Mr Prescott later met a 60-strong "eclipse flying squad" of police and military motorcyclists, who are being dispersed around Devon and Cornwall to help sort out traffic problems as quickly as possible.

John Prescott: "The A30 is transferring something like 25,000 vehicles from existing roads"

It is the first time military motorcyclists have been used in such a situation, and they aim to get broken-down vehicles off the main roads within minutes.

"These guys know what to do," said Mr Prescott. "They will do a damned good job."

However, Mr Prescott's apparent encouragement of the motorist was criticised by transport pressure group Transport 2000.

"He should have advised people to come by train," said a spokesman. "We don't want to see one long traffic jam from Penzance to Bristol."

All roadworks removed

Meanwhile, finishing touches were being put to other plans to deal with the extra crowds.

The BBC's Dominic Arkwright: "The nightmare begins when you get in your car"

Electronic motorway signs, media broadcasts and the Eclipse 99 Traffic Centre's Website have flickered into life to keep motorists up-to-date with conditions.

All roadworks have been removed from main arteries to the southwest.

Fire chiefs have set up temporary stations around the county and doubled the number of firefighters available.

South West Water has installed 10 temporary booster stations to help keep up water pressure during periods of very high demand.

And supermarkets across the south-west are taking delivery of extra food stocks in order to cope with the demand from eclipse-watching tourists.