Piers Morgan, who condemned Justin Trudeau and said he should resign for blacking up his face when he was a student, is pictured here wearing the uniform

This is totally unacceptable. We will not tolerate attacks on our police and perpetrators will feel the full force of the law. It is clear that far right groups are causing violence and disorder in central London, I urge people to stay away. https://t.co/4fzPEbwCQD

Trouble broke out at a much bigger gathering in London called by groups including Britain First who urged people to guard monuments around the nation.