Choosing his moment with care, Toyin Agbetu pricked the calm order and self-serving gloss of a service at Westminster Abbey yesterday to commemorate the bicentenary of Britain’s abolition of the slave trade.

In full view of television cameras and only 10ft from the Queen, Mr Agbetu sprang from his seat in the north transept and took centre stage in front of the altar, shouting to a packed congregation, many of them the descendants of slaves, that they ought to be ashamed of themselves.

A well-known and articulate campaigner on behalf of British Africans, Mr Agbetu, 39, sat through three quarters of the service without a murmur. But, in what appeared to be a moment of exasperation as the proceedings moved to confession and absolution, he had his say.

Agu Irukwu, senior pastor of the Redeemed Christian Church of God, was at the lectern finishing a brief address on how 12 million people world-wide were still in slavery when Mr Agbetu shouted to the congregation at large: “You should be ashamed. We should not be here. You are standing there disrespecting your ancestors. This is an insult to us. I want all the Christians who are Africans to walk out.” No one moved.

Abbey stewards, uncertain of whether this was the right moment for a full-scale confrontation, moved to surround Mr Agbetu. Two of the Queen’s police protection officers moved in to take charge; there was a scuffle and one was knocked to the floor. The Queen looked on, apparently unruffled but undoubtedly interested.

“Let go of me,” Mr Agbetu shouted repeatedly as police and stewards tried to usher him out. Tony Blair and other leading politicians watched in fascination from their seats in the nearby choir stalls.

Above the shouting and kerfuffle the clergy could faintly be heard as they tried to carry on with the service as though nothing had happened.

Mr Agbetu was eventually escorted outside, where he demanded that the Queen and the Prime Minister apologise for the slave trade. “The Queen has to say sorry,” he said. “It was Elizabeth I. She commanded John Hawkins to take his ship. The monarch and the Government and the Church all in there patting themselves on the back.”

Before being taken away by police for questioning, Mr Agbetu added: “This nation has never apologised. There was no mention of the African freedom fighters. This is just a memorial to William Wilberforce.”

Mr Agbetu, who is of Nigerian origin but was brought up in East London, was invited to the Abbey as a representative of Ligali, a London-based group that campaigns on behalf of British Africans. He is a well-known spokesman and writer to newspapers, and is active in trying to reduce gun crime among young blacks.

Henry Bonsu, who runs a black radio station, was among the first to try to restrain Mr Agbetu and calm him. “He’s a friend of mine. Everybody knows him. He wasn’t threatening the Queen, or the Prime Minister or anybody else. He just had a point to make.”

David Burden, Receiver-General of the Abbey, agreed that Mr Agbetu had at no time posed a physical threat. “He obviously felt strongly and in such, fortunately rare, circumstances it is sensible to allow people to speak for a short time before inviting them to leave – if necessary with some assistance.”

Abbey officials expressed regret that the outburst had interrupted the flow of “a deeply meaningful service”.

Under the Abbey’s seated and contemplative statue of Wilberforce, close to his grave, and surrounded by memorials to other equally active if less honoured abolitionists, the congregation heard the Archbishop of Canterbury, Dr Rowan Williams, preach a sermon emphasising that slavery has not gone away. “In the forms in which it is still around today – debt slavery, sex trafficking, forced labour, child abduction and exploitation, it is an offence against the created order of equality,” he said.

Of the 18th-century transatlantic slave trade, Dr Williams said: “We who are the heirs of the slave-owning and slave-trading nations of the past have to face the fact that our historic prosperity was built in large part on this atrocity.”

At a service at Bristol Cathedral last Sunday, a black African group staged a protest with banners and chants of “Not in our name”. It was another indication that the descendants of slaves can still find the white man’s attitude patronising.

Explore UK News

• Crime News

• Education News

• Health News

• Scotland News

Times Recommends

• The bright side of this winter rain
• Story behind the picture: Snow Leopard, 2008
• Times Charity Appeal: The Place2Be