Tories demand apology over Welsh secretary video
Conservatives have accused Labour Welsh Secretary Jo Stevens of bringing the Wales Office into disrepute by using its facilities for "pure party political gain".
Shadow Welsh Secretary Byron Davies said an interview with the minister was recorded in the department's office, breaking civil service rules preventing use of official resources for party political purposes.
But The Wales Office said there was "nothing improper in expressing regret about the manner in which the previous administration conducted itself".
In May, the then Conservative Welsh Secretary David TC Davies appeared to use a government office for a video criticising the Welsh government, prompting similar criticisms by Stevens.
Byron Davies - whose title is Lord Davies of Gower - has written to Stevens asking for an explanation and apology over the latest spat.
He wrote: "In the video posted earlier this week, the secretary of state for Wales said: 'I was very clear about what we, as a government, wanted to achieve and what I wanted to achieve in this role on behalf of the Wales Office, which was to reset the relationship with Welsh government, so moving from that sort of squabbling, fractious, tense relationship'."
The Tory peer added: "The video, which was filmed inside the department and posted across social media, is highly political in nature.
"It is shocking to see taxpayer-funded resources being misappropriated for pure party-political gain."
He said it was in breach of the civil service code and, "therefore, I call for a swift investigation to uncover the full details of why this situation was allowed to unfold".
The Wales Office said: "The secretary of state outlined government policy regarding the reset of the relationship between the UK and Welsh governments.
"There is nothing improper in expressing regret about the manner in which the previous administration conducted itself and the disrespect that it had for the Welsh government and devolution."
It went on to say that the civil service code applied to civil servants, not ministers.