Around 1,000 EDL protesters have made their way along Whitehall before taking a position on the pavement across the road from Downing Street.
A much smaller group of anti-fascist demonstrators gathered opposite them holding an "EDL Racists" banner.
Both sides traded insults but were kept apart by officers and barriers.The EDL supporters chanted: "We hate Cameron."
More top news
Londoners who have received new electronic gadgets for Christmas are being advised to take simple steps to protect them from thieves.
The Boxing Day sales got off to a flying start with shops reporting a surge in business during the first hour of trading.
Bus strikes are planned for Monday 29 December and Monday 5 January.