 Estimates of the warhead numbers transported during this period are that 88 were moved from Aldermaston to Coulport while 120 were returned, indicating a withdrawal of between 30 and 50 warheads leaving an operational stockpile of between 170 and 150 warheads.In the event of a nuclear accident the SSC would activate the MoD's Nuclear Accident Response Organisation and would alert the local police constabulary immediately.The responsibility for these operations rests with the Director Nuclear Movements & Nuclear Accident Response Group.