Security minister Lord West last night claimed that 'another great plot' is being investigated by the police and security services.
The warning of a potential new terrorist attack came as a dramatic intervention in a House of Lords debate over new terrorism powers.
Lord West, the Home Office's counter-terrorism minister, declared: 'There is another great (terrorist) plot building up again and we are monitoring this.'
The threat is 'huge', he added. The former head of the Royal Navy, and part of Gordon Brown's so-called 'Government of all the talents', gave no further details.