London: Amid warnings that an attack by al-Qaida is imminent, Britain has tightened security measures and put a rapid reaction force of Army and a squadron of fighter jets on permanent standby, reports said on November 10.

The pilots have already had psychological training to prepare them for the task of shooting down any civilian aircraft being used as a terrorist weapon, the 'Sunday Observer', a weekly reported.

Special fighter jets, termed Quick Response Aircraft, have been based at RAF Marham in Norfolk, RAF St Mawgan in Cornwall and RNAS Yeovilton in Somerset to provide additional cover from hijacked planes, it said.

Plans for a 'Reserve Reaction Force' will be in place by the end of next month to help the emergency services. Numbering up to 6,000 reservists, the RRF has been divided across the country into 11 brigades.

Police snipers are being trained to kill suicide bombers and anti-radiation pills are being distributed to hospitals, the reports said.

Another report in 'The Sunday Times' today, said ministers and civil servants had to be evacuated from their offices in Whitehall (seat of the government), last week after an anthrax scare at the heart of government.

British Environment Secretary Margaret Beckett had to end a briefing with Tom Ridge, US President George Bush's security adviser, when traces of white powder were found.

The security alert led to the evacuation of offices at the Trafalgar Square and meeting was brought to an abrupt end with the officials being shepherded out of the building by a back entrance to the Horse Guards Parade.

PTI