The secret world of Russia football hooligans
16 February 2017 Last updated at 03:39 GMT
At the 2016 European Championships, violent clashes between Russian and English supporters in Marseille put the spotlight on Russian hooliganism.
Russian hooligans injured over 100 English supporters, beating two into a coma.
It has raised serious concerns ahead of Russia hosting the 2018 World Cup.
In rare interviews with members of the Orel Butchers - who violently attacked English fans in Marseille - a world is revealed where brutal violence has become a mark of honour.
Watch the full programme Russia's Hooligan Army, BBC 2, on iPlayer, first broadcast Thursday 16th February
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