During the question and answer session on LBC, presenter and Sunday Express columnist Nick Ferrari read out a question from a listener.
He said: “Nathan says ‘what should happen to an MP who doesn’t speak in Parliament in over a year and takes two months to officially resign?'”
With the Prime Minister laughing in the background, Mr Ferrari went on: “I think he might be talking about your colleague Nadine Dorries who hasn’t spoken in Parliament since July of last year.”
Mr Sunak responded: “Look, I think people deserve to have an MP that represents them wherever they are.
“It’s just making sure your MP is engaging with you, representing you, whether that is speaking in Parliament or being present in their constituencies, doing surgeries, answering your letters.
“That’s the job of an MP and all MPs should be held to that standard.”
Ferrari asked: “She’s failing in that?”
And in a blunt comeback, Mr Sunak said: “At the moment people aren’t being properly represented.”
Ms Dorries has been a leading critic of Mr Sunak blaming him for the coup which removed Boris Johnson last year and then the second coup which saw him replace Liz Truss.
She has used her TalkTV show to criticise the Prime Minister and is due to publish a highly anticipated “who dunnit” book on the events which saw Mr Johnson removed from office.
But friends have come out in support of her.
Claire Bullivant from the Conservative Post and chief executive of the Conservative Democratic Organisation, a grassroots group set up by Boris Johnson allies for members to take back control of the party from MPs, insisted Ms Dorries is “one of the busiest people” she knows.
She said: “She never stops helping people (and also animals!) in her constituency and beyond.
“She’s also hugely instrumental as a Patron of the CDO fighting for democracy and for the grassroots to have more say. Nadine is a true conservative and patriot.
“No one should believe the left-wing media who are peddling this narrative that since she resigned she’s sat at home doing nothing.
“This couldn’t be further from the truth. Nadine never stops. Even now when Parliament is in recess, Nadine is still working and also helping us massively at CDO to save our party and give members more say.”
Another source said: “I think it’s rich coming from the Prime Minister who didn’t even bother to go out and campaign during the local elections.”
Other allies noted that they do not believe the country is being properly represented at the moment by the Sunak Government.
One senior Tory backbencher noted: “The country is not being properly represented by an unelected Government and PM walking all over the British public with policies that hurt them and our country.”
The comments from Mr Sunak follow claims made in a letter by Flitwick Town Council which alleged she had not held a surgery in three years in the largest town in her Mid Bedfordshire constituency.
Mr Sunak praised the local Police and Crime Commissioner Festus Akinbusoye who is due to be the party’s candidate in the constituency at the next election.
But some Tory MPs were left wondering if Mr Sunak really wants another by-election after losing Selby and Ainsty to Labour and Somerton and Frome to the Lib Dems, both with 2019 Tory majorities of around 20,000.
In 2019 Ms Dorries won the seat with a majority of 24,664.