Mr Johnson responded: "It is absolutely vital that fans who are preparing to go to Russian Federation for the World Cup, and we are not actively trying to dissuade them, we don't think that would be right, they should look at our keep on the ball website, they should look at the risks that we believe may be associated with any particular venues". The head of football policing warned the flag can be "antagonistic" and could lead to violence. "It can come across as nearly imperialistic. and can cause antagonism", he said.
The National Cyber Security Centre (NCSC), an offshoot of Britain's surveillance agency, has warned fans to set up extra email protections and avoid accessing internet banking ahead of the tournament, which kicks off next month.
"We would not expect people to come across to this country, get drunk and drape flags on the Cenotaph, so we need to extend the same courtesy when we go overseas", he said. He pointed out that most British football fans were seasoned travellers.
English fans have been told be on their best behaviour in Volgograd - formerly Stalingrad. As a result, the city is home to a number of important war memorials.
"Russians are fascinated with English fans".
Deputy Chief Constable Roberts said that England's "appalling" behaviour by football fans before a friendly match against Holland in Amsterdam in March - witnessed by Russian police - had been "incredibly unhelpful" to assurances that supporters would behave themselves during the World Cup.
England supporters in France for Euro 2016 clashed with Russian fans, who posted pictures of dozens of "captured" St George flags.
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