A SOUTHAMPTON mum has sparked a major security alert at Whitehall after sneaking unchallenged into the heart of govern-ment offices.

Giulia Gigliotti has today told how she spent 24 hours in police custody after breaching tight security at the Cabinet Office.

The 47-year-old was among four anti-war protesters who breezed past guards just minutes after the Queen had announced new measures to tackle terrorism.

Ironically, Whitehall had been swamped with armed police for the reopening of Parliament.

The campaigners walked through the main entrance on Tuesday lunchtime before putting on outfits covered in fake blood.

They were only arrested on suspicion of burglary after demanding to speak to "those responsible for the killing in Iraq".

All four activists were taken to Charing Cross police station, where they were released without being questioned at 1.30pm yesterday.

Ms Gigliotti, of Sherborne Road, Highfield, her friends Rosie Bremner, artist Liz Jones and anti-war protest veteran Les Gibbons have all been bailed until February 2, pending further inquiries.

Today, mother of two Ms Gigliotti, a former Greenham Common protester, described how the friends had wandered unchallenged in the Cabinet Office for 20 minutes.

"We couldn't believe how easy it was to get in," she said. "Nobody stopped us and we walked upstairs and went into an office and asked if we could talk to someone about our protest."

She added: "We spoke to a man in a suit who said: 'I'm very surprised to see you here'. Then he went to fetch a security guard. We all decided to stage a die-in and laid on the floor.

"No one tried to really move us on and we were surprised at how long we were able to stay in there.

"We continued our die-in for about five minutes before we decided to leave. But as we were leaving, police officers stopped us and arrested us. It was a terrible ordeal and they held us for 24 hours. They strip-searched us and took our mobile phones away."

Police also searched Ms Gigliotti's home and those of her friends, seizing computers, floppy disks and notebooks as part of their inquiries.

Last night a Cabinet Office spokesman said an urgent security review was under way.

Back at work today, Ms Gigliotti said the group had wanted to re-focus media attention on the "continuing escalation of violence in Iraq".

It is not the first time Ms Gigliotti has sparked major security alerts.

A long-term anti-war campaigner, she twice scaled the fences of a high-security RAF base in Gloucestershire in protest at NATO's bombing campaign in the Balkans in 1999.

Organisations in which she is involved include Communities Against Toxics, Network Against The War and Aldermaston Women's Peace Campaign.

In March last year, she led a protest outside Vosper Thornycroft in Woolston, Southampton, after the firm won a major defence contract.