Commons security measures are unveiled

Urgent new security measures for the House of Commons were unveiled today to combat terrorist attacks by suicide bombers and the new threats of anthrax and poison chemicals.

In the worst-case scenario, where the capital was contaminated with chemical or biological material, Parliament will be evacuated from London for the first time in 300 years to a secret location.

The evacuation plan - disclosed exclusively by the Evening Standard a month ago - was confirmed in a security briefing to Commons staff by the Serjeant at Arms, Sir Michael Cummins. He said: "If for whatever reason, either or both Houses are unavailable to sit in their Chambers, alternative locations are planned and available within and outside London."

Parliament last sat outside London in 1681, when suspected Catholic plots forced MPs to flee to Oxford. Sir Michael, in charge of Commons security, said the threat level to the country was "high" and the Palace of Westminster was considered a major terrorist target. But he added:

"There is no specific threat to Parliament at this time."

The risks were underlined when Tony Blair was hit by a flour bomb during Prime Minister's Questions last month. Had it been anthrax, the Cabinet and dozens of MPs could have been killed. New guidance to staff includes instructions if a real attack is mounted. They include:

Advisers are also recommending a scheme as part of a long-term review of security in which some of London's busiest roads are closed to prevent lorry bomb attacks on Parliament. The plans, which have gone to Cabinet ministers, include closing a section of Bridge Street, between Westminster Bridge and Parliament Square, and paving over the road fronting the Commons.