Campaigners also turned out in Walthamstow to demonstrate against the English Defence League.
The English Defence League demonstration was briefly interrupted by anti-fascist protesters. They were led away by officers before there was any confrontation.
Members of the far-right English Defence League have been staging a protest in Westminster.
Around 40 members of the English Defence League are holding a demonstration outside Parliament today.
The group were denied permission to march through Walthamstow by the Home Secretary.
Far-right group English Defence League (EDL) will protest outside Parliament today.
The EDL originally planned to demonstrate in Walthamstow, but the MET Police banned all marches there for 30 days.
EDL says it's a movement opposed to Islamic extremism, but critics say it's racist.
Waltham Forest Councillor Chris Robbins says the ban "is a victory for the ordinary residents."
But EDL has told the police it will try to stage more protests there once the ban is lifted.
A planned march by the English Defence League through Walthamstow this weekend has been banned by the Home Secretary.
The ban prevents all marches in Waltham Forest, Islington, Tower Hamlets and Newham for 30 days.
Protesters will be allowed to gather outside the Houses of Parliament for an hour.
Police say they were concerned there would be serious disorder if the march went ahead.
Chief Superintendent Peter Terry said: "We have made this decision based on specific intelligence and information, and our message is clear, we do not want people coming into the areas to attend these events."