Senior politicians and members of the Royal family have joined mourners at the Iraq memorial service.

The prime minister joined families of the 51 servicemen killed in the Iraq War at St Paul's Cathedral.

It has proved to be a difficult event for many of those attending and follows weeks of tense discussions. Early calls for a parade were rejected to avoid giving the impression of triumphalism at a time when British troops are still stationed inside the country.

The service takes place with the Hutton Inquiry having raised serious questions about the lead up to the conflict.

Two terrorist attacks in Iraq yesterday also showed the peace in the country is still a long way from being won.

Number 10 has been engaged in a series of difficult talks with the new head of the Church of England, Dr Rowan Williams, who is set to lead the service.

The Archbishop of Canterbury, who had been a strong opponent of the war in Iraq, told Number 10 he would find it awkward to lead a service of thanksgiving.

And there has been a mixed reaction from the families over the presence of Tony Blair at the ceremony.

The father of one of the dead soldiers had called for the prime minister to stay away.

"Mr Blair should resign and disappear quietly. He definitely should not turn up at the memorial service," said Gordon Evans.

"He's just a puppet of Mr Bush, and the rest of Europe did not want to get involved. He's the one who sent out troops in the first place.

"We wouldn't be having a memorial service if it wasn't for him."

But Number 10 said there had been consultations with the families of the dead service personnel.

The official spokesman said it was right that the prime minister should attend a national occasion.

"I think the nation would expect the prime minister would be present to help lead the nation in its prayers for those who died and those who served in the conflict," said Downing Street.