A record number of suspected England
hooligans will be banned from Euro 2004 as police aim to ensure it is remembered for football, not violence.
Police want to stop any suspected hooligans getting to Portugal
Nearly 2,700 people are subject to banning orders or bail conditions stopping them travelling to Portugal next month, the Home Office says.
During Euro 2000, the number of banning orders in place was just 100.
Police will have officers at ports and airports at home and abroad on the look-out for known hooligans.
The Home Office said stepping up the use of banning orders was part of the most extensive multi-agency plan for an overseas football tournament in UK history.
Some 50,000 to 60,000 people are expected to travel to watch England's matches, but it is not just the known trouble-makers who will be barred.
"The Portuguese have made it clear that anyone else who is known to pose a risk to public order will be denied entry," said Home Office minister Caroline Flint.
"We believe we've done everything we can to ensure a safe and enjoyable tournament.
"Everyone involved wants it to be a genuine festival of football. We are determined not to let a thuggish minority ruin the tournament for genuine supporters."
Home Office minister Caroline Flint is hoping for trouble-free finals
A team of Portuguese immigration and border police will be stationed in England during the tournament, speeding up decision-making by the Portuguese
authorities on whether to allow fans into the country.
British officers will advise Portuguese immigration officials at points of entry in Portugal.
From midnight on Tuesday, border controls scrapped in 1991 were restored by Portugal, as part of its security measures in the run up to the championships, which start on 12 June.
The move was formally approved several weeks ago, prompted by concerns about both hooliganism and terrorism.
Police accept that with an estimated 200,000 British holidaymakers also in Portugal next month, there is bound to be some drunken violence, although not necessarily directly linked to football.
But they say that if the threat of football violence does flare up at England's matches in Lisbon or Coimbra, a different type of policing will be seen to that of previous Euro finals.
David Swift, head of the British police team at Euro 2004, said: "Some European countries stand back, wait for the trouble and then send in the riot squad.
"We will be trying to focus on the problems before they materialise and then intervening. The final backstop will be a riot squad."
Police are keen to stress that they consider the vast majority of England fans going to Portugal as genuine, law-abiding supporters who do not want to be tarnished by the shame any hooligans could bring on English football.
Uefa, European football's governing body, has threatened to ban England from European competition if there is a repeat of previous violence.
Ms Flint said: "Our best endeavours are about trying to make sure that is a decision Uefa doesn't have to take."
However, one MP has echoed the fears of some football supporter groups that genuine fans may also fall foul of the police crackdown.
Stephen Pound, Labour MP for Ealing North, said the number involved in banning orders made him wonder whether the police had cast their net too far.
"I hope that it is not over-reaction and that this is specifically targeted. If not, there are going to be a lot of very unhappy football supporters," he said.