The Metropolitan Police have launched a major security operation ahead of England's European Championship clash with Scotland on Friday amid fears of a mass invasion by the Tartan Army.
Hundreds of officers will form a ring of steel at Wembley to prevent ticketless fans accessing the stadium, and there will be a significant police presence in tourist areas of London such as Trafalgar Square, as well as at Kings Cross and Euston stations.
Scotland have a ticket allocation of 2,800 in the reduced capacity crowd of 22,500, but thousands are expected to travel to London regardless.
All 32 trains departing Edinburgh and Glasgow for the capital are fully booked, and southbound services from Manchester are also extremely busy.
There are also concerns about Scotland fans infiltrating the home areas of the stadium as tickets are still changing hands on various resale websites.
The police will work with stewards to stop ticketless fans accessing Wembley Way, and travelling fans in the England sections risk being ejected from the stadium.
Hundreds of officers will form a ring of steel at Wembley to prevent ticketless fans accessing stadium on Friday. Pictured fans outside Wembley ahead of England's match against Croatia
Thousands of Scotland fans are expected to travel to London for Friday's match at Wembley
The Met's Deputy Assistant Comissioner, Jane Connors, told Sportsmail the force were preparing to deal with an invasion of ticketless fans for Scotland's first game at Wembley since a World Cup qualifier five years ago in what will be only their second tournament meeting in 114 fixtures.
'We anticipate a significant number of fans are expecting to travel to London,' Connors said.
'I would urge people: please, only come to London if you have a ticket for a match, or fanzone. There are no alternative sites for fans to gather in large numbers and there are limited spaces in pubs and bars and you could end up missing the game. London is still in lockdown and must observe current Government guidelines.'
There will be a significant police presence in tourist areas of London before the match
Paul Goodwin of the Scottish Football Supporters Association said Steve Clarke side's defeat by the Czech Republic may have deterred fans from travelling and complained about the lack of a fanzone for the visitors in London.
'There's less likely to be a mass invasion as people are feeling deflated after the Czech result, but there will be a few thousand without tickets, that's for sure,' Goodwin said.
'In addition to those travelling, as someone who lived in London for 16 years I know how big the Scottish community is down there.
'The official allocation is 3,000 so it could be double that or even more. A Scottish fanzone would have helped keep people away from Wembley. Maybe that decision was taken to stop people from travelling.'
Scotland fans gathered in Trafalgar Square back in 2013 for a big match against England