Wales's deputy transport minister has accused the Welsh Conservatives' newest member of trying to unravel devolution, on her first day back in the chamber.
Lee Waters MS tweeted that Laura Anne Jones, the Senedd Member for South Wales East, was "trying to unravel devolution" after she tweeted a story about Boris Johnson wanting to give the go-ahead for the M4 relief road past Newport allowing a "proper M4 bypass".
The prime minister made the statement in the House of Commons saying, "We will do the things the Welsh Government has failed to do - such as unlocking the Brynglas tunnels allowing that M4 bypass which has long been needed."
The decision whether or not to build an M4 relief road is the responsibility of the Welsh Government, and one which First Minister Mark Drakeford announced would not be happening last year.
Following Boris Johnson's comments, Ms Jones said: "The best news.. well done Boris. Hope he can make this happen."
Ms Jones, is the Senedd's newest member, representing the Welsh Conservatives. She has previously been an Assembly Member but lost her seat before returning recently to take up the seat of Mohammad Asghar, who died suddenly in June this year.
An M4 relief road around Newport has long been a source of controversy with years of wrangling over whether it would or would not happen. The stretch of road around newport is notorious for its long tailbacks.
In its 2016 manifesto, Welsh Labour said: "We will deliver a relief road for the M4" but last year the First Minister, Mark Drakeford, announced that the relief road would not be going ahead due to concern over its environmental impact.