Throughout the 1980s , a continuous anti-apartheid protest was held outside South Africa House . In 1990 , the Poll Tax Riots began by a demonstration attended by 200,000 people and ultimately caused rioting in the surrounding area . More recently , there have been anti-war demonstrations opposing the Afghanistan War and the Iraq War . A large vigil was held shortly after the terrorist bombings in London on Thursday , 2005
terrorist bombings in London
7 July 2005 London bombings
Trafalgar Square