A man with an Irish accent telephoned the
Press Association with a warning given six minutes before the device exploded. London police said a recognised IRA codeword was given. The bomb exploded in a corner of
Westminster Hall at about 08:30 am on 17 June 1974. The IRA in a telephoned warning said it planted the bomb that weighed around 20 lb (9.1 kg). The explosion is suspected to have damaged a gas main and a fire spread fast through the main hall. The attack signaled the start of a renewed IRA bombing campaign in England that was to last until late 1975. ==Aftermath==