THE leader of Plaid Cymru in Westminster has called on Tory MPs to "grow a backbone" and oust the Prime Minister following the publication of the Sue Gray report into the Partygate scandal.

Liz Saville Roberts MP's calls on the Prime Minister to resign where met with a 'no' response from Boris Johnson in the House of Commons after he was pictured at gatherings at a number of gatherings in 10 Downing Street while the country was subject to strict Covid-19 restrictions.

The report was published on Wednesday (May 25) and includes a series of pictures showing Mr Johnson and Chancellor Rishi Sunak at the former's birthday party along with other events.

It criticises the PM saying that “the senior leadership at the centre, both political and official, must bear responsibility for this culture.”

Ms Saville Roberts said that as Mr Johnson can no longer use Sue Gray as a “human shield”, it is down to Tory MPs to “grow a backbone and oust this moral vacuum of a Prime Minister”.

Under the ministerial code, ministers who 'knowingly mislead parliament' will be 'expected to offer their resignation to the Prime Minister', including the Prime Minister himself.

Speaking in the House of Commons, Ms Saville Roberts MP said: “To call this a damning report for the Prime Minister is an understatement. It states that ‘the senior leadership at the centre, both political and official, must bear responsibility for this culture’.

“For 168 days, he has used Sue Gray as a human shield against this duty. In this farce of a parliamentary system, it’s now all down to Tory MPs to grow a backbone and oust this moral vacuum of a Prime Minister.

“Will he spare them the trouble and resign?”

The Prime Minister responded: “No, Mr Speaker.”

Adding to Ms Saville Roberts’ comments, Cefin Campbell, Plaid Cymru Member of the Senedd for Mid & West Wales, has urged Powys' Conservative MPs, Craig Williams (Montgomeryshire) and Fay Jones (Brecon & Radnorshire) to publicly call for the Prime Minister’s resignation.

In her report Ms Gray said “many will be dismayed that behaviour of this kind took place on this scale at the heart of Government” and “what happened fell well short” of the standards expected.

And she also said she learned of multiple examples of “unacceptable” treatment of security and cleaning staff during her Partygate investigation.

But she also concluded that “it was not appropriate or proportionate” to make further inquiries after the Metropolitan Police's investigation.

The Metropolitan Police has issued 126 fines for rule breaches in No 10 and Whitehall, with the Prime Minister receiving a single fixed-penalty notice for his birthday party.

In response to the report Mr Johnson said: "I also want to say above all that I take full responsibility for everything that took place on my watch.

"Sue Gray’s report has emphasised that it is up to the political leadership in Number 10 to take ultimate responsibility and, of course, I do.”