The Government is facing fresh questions over why Mr Farthing was helped to evacuate when the same whistleblower claimed just five per cent of refugees who requested assistance were helped by the Government and many have been subsequently murdered by the Taliban.

The move was criticised by MPs, including Tom Tugendhat, the chairman of the foreign affairs committee.

Dominic Dyer, a volunteer at the charity Nowzad, said he contacted Mrs Johnson directly to ask for her help in evacuating Mr Farthing and believes she asked Mr Johnson to intervene.

‘Neither the Prime Minister nor Mrs Johnson were involved’

He told LBC on Tuesday that “the Prime Minister intervened with the Home Secretary to put those people on the rescue list”, saying: “We didn’t meet him…but we lobbied all the ministers and obviously I knew Carrie Johnson. I made it very clear, my concerns to her. No doubt she spoke to him.”

Asked whether the claims were true, Mr Johnson said “No, that’s complete nonsense. But what I can tell you is that I think that Operation Pitting, to airlift 15,000 people out of Kabul in the way that we did over the summer, was one of the outstanding military achievements of the last 50 years or more.”

Mr Johnson’s official spokesman said that “neither the Prime Minister nor Mrs Johnson were involved,” and denied that she had been lobbied by Nowzad.

The fresh row over Mr Farthing and his rescue dogs comes in the wake of a witness testimony by Raphael Marshall, a 25-year-old Foreign Office official who worked on the evacuation of Afghan refugees in August.

Mr Marshall claims a “dysfunctional” and “chaotic” Whitehall operation meant many civilians were left in Afghanistan at the mercy of the Taliban, rather than being airlifted to safety.

Dominic Raab, the foreign secretary at the time, played down his claims and suggested he did not understand the full extent of the Government’s work to evacuate people from the country.