Exposing the affairs of MPs is being described as 'very foolish'.

Judith Collins this morning revealed she'd been tipped off by a member of the public about inappropriate behaviour involving a minister.

The Prime Minister subsequently sacked Iain Lees-Galloway from cabinet after details emerged of an affair with an ex-staff member.

Former Labour party president Mike Williams told Heather du Plessis-Allan Collins broke an unwritten Parliament rule by publicising things.

"There has been a sort of mutually assured destruction rule going on here, where you don't mention people's affairs, and she brought one out into the open. I think that's very foolish." 

However, Williams says that while many MPs ave affairs with each other, having an affair with staffers is a "big no-no", as it creates a "power balance". 

He says that Parliament is a massive workplace where people are working long hours and socialising with each other, which sees relationships develop. 

• Iain Lees-Galloway sacked for 12-month relationship with staffer