A Conservative cabinet minister who has been accused of breaching ministerial code after he was seen to apparently use his Government office in London to film a video against the opposition on social media has claimed the video was done for ‘security reasons’.

David TC Davies, secretary of state for Wales and MP for Monmouth, posted the anti-Labour video to his social media last week.

Now Jo Stevens, Labour’s shadow Welsh secretary, has now written to the director of the Welsh Office – the civil servant responsible for his office – to ask them to establish whether a breach has occurred and to investigate how it happened.

The short film, dated Wednesday, May 8 which was shared on X, formerly Twitter, and includes Mr Davies speaking about the Labour Welsh Government's plans to extend the size of the Welsh Senedd and details the Welsh’s Conservative Party’s strict opposition to the move.

In the video, Mr Davies can be heard claiming that the Welsh Labour government had to decide whether it wanted to spend £120 million of taxpayers’ money on more Senedd members or increase the number of nurses, doctors, dentists and teachers, as the Conservatives would do instead.

He then says: “I know which side I am on.”

The Welsh Labour Party argues using his official Government office to film such a video is a breach of the ministerial code, but a government source that it was done in the office for “security reasons”.

The ministerial code states: “Ministers are provided with facilities at Government expense to enable them to carry out their official duties.

“These facilities should not generally be used for party or constituency activities.”

Shadow Welsh secretary Jo Stevens' letter states: “The Welsh Secretary posted on the social media site X a video filmed in his private office, which contained explicitly party-political content, criticising the ‘Welsh Labour Government’ for its proposals on Senedd reform, and endorsing the opposition to those proposals from the “Welsh Conservative Group”.

“He closed with the line: “I know which side I’m on, I wonder what Welsh Labour are going to do today.”

She added: “In your capacity as the director of the Secretary of State’s Office, can I ask you to establish whether a breach of the Ministerial Code took place in this instance, and if so, what action will be taken to investigate how that happened, to ensure that it never happens again, and to issue a formal apology from the Secretary of State.”

The Argus approached Mr Davies for comment.

A UK Government source said: "A 30-second video was recorded inside for security reasons."

The nature of these security reasons has not been disclosed to the Argus.