Police officers are carrying out checks at Heathrow Airport to stop football hooligans going to the World Cup.
Police have been checking on fans at Heathrow
Officers are also checking tickets and travel plans across England, to try to stop anyone flying while on a football banning order.
Those on the order have to hand in their passports before the tournament, but up to 200 have not done so.
A man was detained at Stansted Airport on Tuesday and has since been banned from travelling to Frankfurt.
Robbie Varle, 20, from Dunstable in Bedfordshire, was barred from attending any football matches for the next three years under the Football Spectators Act.
There are about 3,500 people on banning orders.
Bob Broadhurst, Gold Commander in London for the duration of the tournament, said a few troublemakers would inevitably get through, but many others would be stopped.
He said: "If you keep out those people that follow the hard core then the hard core are isolated.
"If they have not got anyone to fight with then they will not fight.
"They have to think carefully, if they are on the periphery, as if they throw bottles then they may end up with a banning order and not be seeing football for a very long time."
The World Cup kicks off on Friday
The checks are part of Operation Jardon, under which national ports have been monitored since Sunday.
More than 80 British police officers will be based in Germany while England are in the tournament and the Met is increasing patrols in London as a precaution.
Cmdr Broadhurst also warned that anyone causing trouble in London would be immediately eligible for a football banning order.
But Malcolm Clarke, chairman of the Football Supporters' Federation, said he was concerned about the tough use of laws to combat soccer violence.
"I would compare it to the issues surrounding anti-terrorism legislation. There is real danger that in attempting to prevent any trouble at football grounds, people's civil liberties are being affected."