The Royal Family are being given extra police protection following intelligence reports that anarchists plan to target them this summer.
Anti-capitalist demonstrators who took part in the May Day riots are expected to try and disrupt the Queen Mother's centenary birthday celebrations on 4 August. Scotland Yard believe anarchists will try and cause a mass disturbance outside Buckingham Palace on 3 June, the anniversary of the Queen's Coronation in 1953.
A police source said extra officers would be on duty at some public functions involving the Royal Family, after a risk assessment of anarchist groups.
Sir John Stevens, the Metropolitan Police Commissioner, said yesterday of the organisers of the May Day riots: "They are anarchists and they want the Royal Family dismantled. They've been quoted as saying that if they can injure as many police officers as possible in the process, so much the better."