Deputy Labour leader Angela Rayner has written to Standards Commissioner Kathryn Stone requesting that she investigate allegations that Sir Geoffrey Cox MP breached parliamentary guidelines.

Rayner wrote: “My understanding of this rule has always been that members were never to use the facilities gifted to them by Parliament and their constituents for their private interests. The Member has clearly broken this rule based on the media reports we have seen.

She went on: “Members must be clear that they cannot use the estate for private financial gain and where there is such a stark conflict with public interest, they must face substantial consequences.”

She added via Twitter that Boris Johnson “needs to explain why he has an MP in his party who treats Parliament like a co-working space allowing him to get on with all of his other jobs instead of representing his constituents.”

This fresh criticism comes after The Times reported on a previously unseen video of Cox participating in a virtual British Virgin Islands inquiry hearing this September from what seems to be his parliamentary office.

Cox has not denied that he used his Commons’ office to carry out external legal work, a clear breach of the Members’ Code of Conduct .