The Times assistant editor Mary Ann Sieghart and Karl Marx biographer Francis Wheen spoke for the motion, while investigative journalist - and scourge of PR people everywhere - Tom Bower and Spectator political editor Peter Oborne spoke against.
All was good-natured fun until a few heartfelt speeches from the floor.
An unnamed PR woman stole the show, hitting back at those who had claimed the Mail was both sexist and historically anti-semitic.
'I am a woman, and Jewish,' she said, 'and my PR business almost went under 'cos of non-payment by clients until the Mail ran a campaign naming and shaming them. I will be forever grateful.'
Before Diary could collar this outspoken PRO, she scarpered - so she may not know that the vote went 318 to 201 in favour of the motion.