We do understand that illegal immigration is very, very nasty for Britain

Daniel Bernard French Ambassador

Downing Street said on Wednesday it has received assurances from the French authorities that the number of police patrolling the entrance to the tunnel had been restored to normal.

But speaking on BBC Radio 4's Today programme, Mr Blunkett said: "The real issue is the closure of Sangatte.

'Cannot carry on'

"Obviously security around the whole facility should be massively improved.

"We have to try sitting down with them and making it clear we cannot carry on in the way that we have so far."

Mr Blunkett: Closure of Sangatte the real issue

He said he would be seeking urgent talks on the situation once the new French government was in place.

There have been repeated calls from Eurotunnel for the closure of the Red Cross refugee camp, near Calais.

But in February Eurotunnel lost a second legal challenge to force the camp's closure.

Later on the Today programme, French Ambassador Daniel Bernard said a "proper solution" needed to be found to the problems at Sangatte.

"If you want to be successful it is not a once-and-for-all solution to close down Sangatte because the causes are still there," he said.

He said there had been "technical problems" at the freight yard at Frethun, during a change-over period in policing at the weekend.

Mr Bernard said there were now 60 police guarding the area, although it was pointed out that only 15 were on shift at any one time.

'Ineffective'

He said: "We do understand that illegal immigration is very, very nasty for Britain but we are facing the same difficulties on a larger scale."

But Graham Smith, of British rail-freight operator EWS, said security was still "ineffective" with less trains running through the tunnel due to the risk of illegal immigrants getting on board.

"We are losing half a million pounds per week because our customers are leaving us to go by roads and ferry," he said.

A total of 11 more illegal immigrants were arrested on Tuesday night after smuggling themselves into the UK through the Channel Tunnel, British Transport Police have confirmed.

Surveillance

Rail bosses said just four out of a scheduled 11 trains came through the tunnel, due to the disruption caused by the would-be asylum seekers storming the freight depot at Frethun.

Illegal immigrants caught in Folkestone

March: 111 April: 304 May: 202 so far Source: British Transport Police

Graham Meiklejohn, spokesman for EWS said: "The level of policing reinstated was 15 patrolling three miles of fence. I think that speaks for itself."

A Downing Street spokesman said the French rail operators SNCF, which runs the depot, was to begin installing better security fences and surveillance equipment next month.

Shadow Cabinet Minister Michael Howard, whose constituency covers Folkestone, said the government was "either not trying or had failed to get the French government to face up to its responsibilities".

SNCF spokesman Eric Martos said the yard had been left short of security from Friday until the squad was returned on Tuesday.

He said the local gendarmerie remained in place all weekend, but proved overwhelmed by sheer numbers - 300 asylum seekers attacked the yard on Friday.