Up to six of the anti-war campaigners at a time filled a pen just a few metres from the door - and cracked open a small bottle of champagne once he had departed.

It ensured that Mr Blair did not depart without the sound of his most controversial legacy ringing in his ears. They were let in after applying to police in writing, which they are required to do under the controversial Serious Organised Crime and Police Act 2005.

The legislation requires police permission before a demonstration is mounted within a mile of Parliament. But until recently, when campaigning comedian Mark Thomas led a number of small protests inside the gates, most events were held on Whitehall.

Among the demonstrators who were granted special permission to protest inside the gates was Rose Gentle, from Glasgow, whose son Gordon was killed in Basra in 2004. Mrs Gentle, 43, who will mark the third anniversary of his death on Thursday, shouted "scumbag" as Mr Blair left for Prime Minister's Questions.

As he returned, and then left for good with his wife, she vocally demanded that he spoke to her, but to no avail. As the Blairs were driven away, she and the other relatives also held up pictures of the loved ones killed in Iraq

Mrs Gentle said: "When he brought his sons out and cuddled them, that made me feel sick. My son died three years ago tomorrow and that is the man that sent him to be killed in an illegal war."

Also in the protest pen were Private Gentle's sister Pamela, 24, and his grandmother, 69-year-old Pauline Graham. Peter Brierley, 56, whose son Shaun was killed near the start of the war, also said he did not expect Mr Blair to take the time to speak to him.

He said: "It is not what I expected to happen as we are here representing one of the biggest mistakes he has ever made and he won't admit it to himself."

Family members representing around 15 members of the British military killed in Iraq were protesting throughout Wednesday, according to the Stop The War Coalition. A letter to Gordon Brown seeking a meeting with the new Prime Minister was handed into Downing Street after the protest. But Lindsey German, of Stop The War, said she did not have much hope that Mr Brown would change the Iraq policy.