Three madmen in a boat: Two Germans and a Frenchman arrested after 'goodwill' mission across the channel

But no one was laughing when Gunter Ludvig, Bernard Druker and Claude Allan landed in Kent after nine hours in the world's busiest shipping lane on what was little more than a few oil drums and sheets of plywood.

The trio, councillors in Folkestone's twin towns of Zweibrucken and Boulogne, intended the trip as a symbolic show of European solidarity and were expecting a heroes' welcome.

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Instead they were arrested, thrown into police cells and held for ten hours on suspicion of endangering life.

Maritime experts likened their enterprise to "crossing the M25 on a scooter with a blindfold on".

"It was just stupid," said Mark Clark, of the Maritime and Coastguard Agency.

"They posed a danger to themselves and other vessels."

His organisation impounded the "unseaworthy" craft - which was without any working safety equipment - breath-tested the men and seized beer and wine from them.

Last night, after being released without charge, the chastened sailors were heading home by rather more conventional means - through the Channel Tunnel.

All in their 60s and experienced at sea, they had spent months planning a journey which had been their dream for 20 years.

They built the raft, the Avec Plaisir III, in Germany before transporting it to France. It was fitted with a makeshift sail, a small 15 horsepower motor, a plywood deck and a metal chest containing provisions.

But they failed to notify the authorities on either side of the Channel of their trip.

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They had no warning beacon to alert other craft to their presence, carried a radio which did not work on the correct frequency, and were equipped with flares which were 24 years old and probably inoperable.

"We're really hacked off with them that they chose to do this," said Mr Clark.

"Anyone who wants to cross the Channel, or even swim across, must notify us first and assure us they have sufficient safety equipment, none of which this lot did."

Mr Allan, 61, who captained the raft, said: "We are very sorry for what happened. We tried to contact coastguards on both sides of the Channel but couldn't.

"We found out later that our radio was broken."

Lynn Dockar, manager of the Boulogne and Shepway Cooperation Association, the council-run twinning organisation, was arrested alongside the men as she waited in Folkestone harbour.

She said: "They were making a symbolic journey across the Channel carrying a message of goodwill. They thought it was a big gesture and it was a dream they have had for 20 years.

"In the space of 20 seconds I went from elation at their joyous arrival to deep concern when two very angry Coastguards appeared.

"We had been assured by the men that they would be requesting permission before they set off. They have said they are deeply sorry they have caused so much fuss."

Up to 500 ships a day, many of them ferries and large cargo vessels, cross or pass through the Channel.

The danger it poses was highlighted a year ago when three City workers were killed after their 25ft yacht sank in a suspected collision with a ferry.

A spokesman for Dover Coastguard said: "Their raft was called Avec Plaisir III. It makes you wonder what happened to the other two."