Jacob Rees-Mogg was unable to name the leader of the Welsh Conservatives when asked in Parliament.
The Commons Leader was asked if he could name Andrew RT Davies by Cardiff West MP Kevin Brennan at Business Questions on Thursday.
It comes after Mr Rees-Mogg, MP for North East Somerset, called Scottish Conservative leader Douglas Ross a “lightweight figure” in the party on television on Wednesday night.
Mr Brennan asked: “Following his disparaging remarks about the leader of the Scottish Conservatives, can we have a statement from him about exactly what he meant by that?
“For example, does he think the leader of the Welsh Conservatives is a lightweight figure? And can he name him?”
After briefly laughing and then remaining silent for a moment, Mr Rees-Mogg replied: “The Secretary of State for Wales is called Simon Hart.”
He was among the Tories to show support for Boris Johnson following a crushing Prime Minister’s Questions on Wednesday, tweeting: “People are hurt, angry and let down at the events of the past 48 hours, and the Prime Minister has rightly apologised. The inquiry by the senior civil servant, Sue Gray, must now be expedited to establish the full facts and report the findings as soon as possible.
“It’s vital the PM continues his work on the booster roll out, which has been world-leading, so we can get Britain on the road to recovery and free from restrictions.”