Protesters booed, chanted “scum” and “what a waste of money” as Margaret Thatcher’s funeral procession passed through London’s Ludgate Circus.
Brandishing Socialist Worker placards urging the “burial of Thatcherism”, there were reports of some scuffles with police being tweeted from the scene.
Other members of the crowds simply turned their backs on the procession. Meanwhile, well-wishers on nearby Fleet Street made efforts to drown out the protesters by clapping loudly.
Patricia Welsh, a 69-year-old retired youth worker, attended the Facebook-organised demonstration.
She told the Press Association: "I am absolutely furious that Prime Minister David Cameron has decided to spend £10 million on a funeral when normal people are having to face cutbacks, libraries are closing and the NHS is being cut - for the funeral of a Conservative woman.
"Like anyone else she deserves a decent funeral, but not at the expense of the taxpayer."
Dave Winslow, 22, an anthropology student from Durham, was joined by three others at Ludgate Circus, next to St Paul's Cathedral, where the funeral service was taking place.
Holding an acrylic placard reading "Rest of us in Poverty" and wearing a T-shirt with the messages "Power to the people" and "Society does exist", he said up to 200 demonstrators were expected.
"We plan to turn our backs," he said. "We want to maintain a dignified protest, it's counter-productive to cat-call and sing Ding Dong The Witch Is Dead.
"The message is that spending £10 million on such a divisive figure in times of austerity, especially when austerity is being imposed on the poor, is wrong, especially when harm is being caused to the disabled and the NHS.
"I think quite a few disabled people have died since being pushed into jobs they're unsuitable for.
"I have a friend up north who skips meals in order to feed a child. The working class are really being crushed by the rising costs of living and welfare cuts.
"The Government wants to glorify this. It is a massive propaganda campaign to idolise Margaret Thatcher."