Winston Peters' attack on his estranged former political protege, Brendan Horan, was a low blow.
Bad blood between Mr Peters and Mr Horan plummeted to new depths on Tuesday when the New Zealand First Leader referred to Mr Horan as "the Jimmy Savile of New Zealand politics".
Mr Peters withdrew and apologised for the remark when asked by Speaker David Carter but the damage was already done. The two have been at odds since Mr Horan was ejected from NZ First in 2012 amid claims he had misappropriated money from his dying mother.
Mr Horan showed dogged determination after his sacking and chose to remain in Parliament as an independent MP, much, it seems, to the annoyance of Mr Peters.
While Mr Horan and Mr Peters have sniped at each other since, the conflict has been particularly bitter recently with Mr Horan, under cover of parliamentary privilege, claiming misuse of parliamentary funding by Mr Peters and also saying he failed to disclose his interest in a racehorse in Parliament's Register of Pecuniary Interests.
Yesterday Mr Horan continued on the same path, alleging NZ First misused parliamentary funding, using it for party political purposes including tens of thousands of dollars for voter management software and the salaries of employees to operate it. Mr Peters says the independent MP's claims are false.
Comparing Mr Horan to the infamous UK broadcaster was out of line.
Sir Jimmy's name has been blackened by hundreds of allegations of child sex offences that emerged after he died three years ago.
The slur goes well beyond robust debate. Grant Duncan, Massey University associate professor and political commentator, says the accusation reduced the debate to a level that was unseemly.
Mr Peters, in my view, used the cover of parliamentary privilege to deliver a cheap shot.