 The radioactive cloud spread to south-east England and fallout reached mainland Europe.Although scientists had warned of the dangers of such an accident for some time, the government blamed the workers who had put out the fire for 'an error of judgement', rather than the political pressure for fast-tracking the megaton bomb.Concerned that public confidence in the nuclear programme might be shaken and that technical information might be misused by opponents of defence co-operation in the US Congress, Macmillan withheld all but the summary of a report into the fire prepared for the Atomic Energy Authority by Sir William Penney, director of the Atomic Weapons Research Establishment.