After two years of planning with police forces all over Europe, Chief Inspector Peter Chapman said measures were in place to snuff out hooliganism at the first sign of trouble.
"We have erred on the side of caution for each game. We will probably have more police inside stadiums than you would usually see at normal Premiership matches."
But visible policing is only a small part of the operation. In the background, the intelligence unit has been liaising with its counterparts in each of the 15 other competing nations. Officers from each country will accompany British officers to help identify troublemakers.
"No one can say that there will not be any trouble," said Mr Chapman. "With so many people - 250,000 fans - some minor disorder is inevitable. It is my job to obtain intelligence to stop that becoming major disorder."
Mr Chapman said no trouble was expected from Czech, Croatian, Bulgarian and Russian fans as most were "simply too poor to afford the travel packages on offer". The Danish, French and Italian teams all enjoyed a good following, he said, but their fans at national level were very peaceful.
Any trouble was likely to centre around English, German and Dutch fans, he said. "Each of these countries have a core of troublemakers, but certainly not in the numbers that have been so sensationally reported in the media," Mr Chapman said.
The main flare-up could come on 15 June when England play Scotland at Wembley. At their last Wembley meeting,hordes of Scots tore up the pitch and ripped down the goalposts.
"We do not expect the same problems this time," said Mr Chapman. "Since then, the Scots have made great strides in ridding themselves of the hooligan element."
Another source of trouble could come from an unexpected quarter - Turkey. "They are arguably the most fanatical fans in the tournament," he said. "Any trouble from them could be politically motivated. They may try to use the event to highlight the plight of the Kurds."Reuse content