Participants in yesterday's anti-badger cull protests were reportedly seen chasing BNP supporters down London's Whitehall, reports the International Business Times.
The BNP and EDL march was opposed formally by activists from groups including Unite Against Fascism and Hope Not Hate.
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The major party leaders' campaigns for the General Election will remain suspended on Wednesday following the Manchester terror attack.
Thousands of people have donated to help the families of the victims - as well as a homeless man who came to their aid.
Some children, particularly those who have been more directly affected, may show symptoms of stress and trauma.