The grave of Karl Marx has been vandalised by yobs who daubed paint on the monument at Highgate cemetery.
The attack on the 12ft plinth and bust, which is thought to be the first of its kind for decades, has been condemned by former cabinet minister Tony Benn and conservationists.
Mr Benn said: "I am very sorry to hear the grave has been attacked. Marx was one of the greatest figures in history. What he said about society was very important, he is still studied the world over and this is not true of many people more than 100 years after their death."
Mr Benn, who has visited the German political philosopher's grave many times, said that despite the attack he still thought most people "respect Karl Marx", and that the Das Kapital author's grave deserved the same regard. Conservationists condemned the vandalism.
Catherine Budgett-Meakin, chairwoman of the Highgate Society, said: "It is one of the big things which people come to Highgate to see. It is appalling it has been desecrated in this way."
Marx, who wrote The Communist Manifesto, lived in Highgate for many years and died there in 1883. At the peak of political radicalism in the Sixties and Seventies Marx's grave was often targeted.