Key quote
"Part of the investigation is to see how far the three women got inside the building and whether they had entered private areas" - Police source

Story in full ANTI-WAR protesters made a mockery of Tony Blair’s key election pledge of security by bursting into a government building just minutes after the Queen had announced new measures to tackle terrorism, it emerged yesterday.

As the whole of Whitehall bristled with armed police, three women and a man by-passed supposedly impenetrable security to gain access to the Cabinet Office, which has a direct underground link to No 10 Downing Street, on Tuesday afternoon.

The breach is the latest security blunder to hit the government. In May, protesters threw flour bombs at the Prime Minister as he stood at the dispatch box.

Ironically, Peter Hain, the leader of the Commons, claimed a few hours after the Queen’s Speech that the threat of terrorist attack was significantly lower under Labour, a suggestion which caused a furious row and left him accused of playing politics with national security.

Although not terrorists, the fact that the four activists were able to gain entry to such a sensitive building, walk past security guards and stage a protest highlighted the ease with which anyone determined to carry out killings within the heart of government could do so.

Three women and a man were arrested on suspicion of burglary and held overnight at Charing Cross police station before being bailed until February. A police spokesman said last night that they "needed more time to pursue inquiries" against the four.

A friend of the protesters said officers had over-reacted and that they were only arrested because police were "embarrassed" they had failed to stop a stunt.

Juliet McBride, a friend of Giulia Gigliotti, one of the women arrested, said clothes and mobile phones were confiscated and the protesters were released on bail wearing just white paper suits.

She said that the Southampton home of Mrs Gigliotti had been searched by police at midnight while her two children slept. Officers seized a computer and floppy disk.

Police said three women were arrested inside the Cabinet Office and a man was detained in the reception area at about 1pm on Tuesday.

It is understood that the women had been inside the building for about 20 minutes before the alarm was raised.

A police source confirmed: "Part of the investigation is to see how far the three women got inside the building and whether they had entered private areas."

The police are checking all offices to see if any property or confidential documents are missing. The protesters are understood to have sneaked by security personnel at the main entrance before donning outfits covered in blood to launch a "die in" protest against the war.

Last night, a spokesman for the Cabinet Office, which houses the Joint Intelligence Committee, said it was carrying out an urgent security review.

Amid the revelations about the security breach, the government unveiled new laws yesterday to give the police powers to move protesters from around parliament. It will mean the eviction of demonstrators who have held a vigil in Parliament Square since the invasion of Iraq.

In September, five people, led by Otis Ferry, son of the pop star Bryan, sparked a security review when they broke into the Commons chamber to demonstrate against the ban on foxhunting. It was the first time parliament had been invaded for 350 years. In May, two members of the Fathers4Justice campaign threw purple flour bombs at Tony Blair during Prime Minister’s question time. In March, two Greenpeace protesters scaled Big Ben.

The Conservatives said the latest security breach proved that "outrageous" and "disgusting" comments by Mr Hain had "spectacularly backfired".

Mr Hain was accused of "playing politics with terror" after he said there was a lower risk of a terrorist attack under Labour than the other political parties.

Last night, Patrick Mercer, the Tory spokesman for homeland security, said: "I said that Mr Hain had made himself a hostage to fortune. I did not think that I would be proved correct so quickly.

"If Labour cannot even get their own in-house security sorted out, what hope have we got for the security of the nation and the Scottish parliament?"

John Major, the former Prime Minister and Dame Pauline Neville-Jones, former head of the Joint Intelligence Committee, also made it clear they disapproved of Mr Hain’s remarks.

But an unrepentant Mr Hain then repeatedly insisted the Opposition parties would leave people less safe and secure.

Dame Neville said: "It is dangerous to start making this into a party political issue."

Mr Major added that it was a "desperate comment" and "very silly".

Mark Oaten, the Liberal Democrat home affairs spokesman, said: "As we tighten up security in parliament we must make sure that other government buildings don’t become the weak links in a system to protect our government and civil service."