From THE BBC:
Mr McDonnell had told a GMB union hustings event that he had been asked what single act he would do to improve the world if he could travel back to the 1980s.
"I said: 'Look, I was on the GMC that Mrs Thatcher abolished, I worked for the NUM and we had the NUM strike, I think I would assassinate Thatcher'." He was applauded by union members in the audience but heavily criticised by commentators.
Nile Gardiner - who worked as an aide to Lady Thatcher after she left office - wrote in his Telegraph blog that Mr McDonnell should apologise "for his disgusting, undignified and menacing words" and attacked them as "a sickening disgrace and a stain on his party".
"It is vicious language of the lowest common denominator that would shame even the worst preacher of hate," he wrote.
COMMENT: The worst preacher of hate?
That would be Margaret Thatcher, then.