Animal welfare campaigners have credited Carrie Johnson for providing hope that a former Royal Marine will be able to airlift his animal shelter staff and 200 dogs and cats out of Afghanistan.

       Paul Farthing, known as Pen, founded the Nowzad shelter in Kabul after serving with the British Army in Afghanistan in the mid-2000s, with the organisation rescuing dogs, cats and donkeys.

       Following the fall of the country to the Taliban, Mr Farthing has been campaigning to have his Afghan staff, their families, 140 dogs and 60 cats evacuated from Kabul’s airport.

       Earlier this week, he secured 68 visas for them to come to the UK. But the plan risked being derailed on Tuesday when Ben Wallace, the Defence Secretary, said the animals would have to wait as he would not prioritise rescuing them over thousands of people trying to escape Kabul on RAF flights.

       But hours later, Mr Wallace announced that if Mr Farthing arrived at the airport with his staff and animals, officials would seek to facilitate their departure aboard a chartered aircraft being funded by private donations.

       On Wednesday night, Foreign Office sources confirmed that members of Nowzad staff had been called forward and asked to make their way to the Baron hotel in Kabul, from which they are expected to proceed to the airport.

       Supporters of the charity said on Wednesday they believed that Boris Johnson and his wife may have played a role in convincing Mr Wallace to drop his opposition to the evacuation plans.

       Mrs Johnson is a prominent environmentalist and animal welfare campaigner, and is involved in a number of conservation projects.

       While claims over the couple’s involvement were strongly denied by Downing Street, multiple Whitehall sources have confirmed to The Telegraph that Trudy Harrison, Mr Johnson’s parliamentary private secretary, had been closely involved in the discussions.

       It is understood that Ms Harrison, who was approached for comment, had raised the issue with the Department for the Environment, Food and Rural Affairs (Defra).

       A number of Tory backbench MPs including Neil Parish, whose constituency is home to Nowzad’s UK address, are also said to have pushed for the Government to help the charity.

       Separately, a close ally of Mr Wallace is understood to have been contacted by a British vet on Tuesday, during which they are said to have stressed that the flight would help rescue both animals and Afghans.

       The change of heart came just hours after Mr Wallace suggested Mr Farthing should leave the animals behind and seek to take them out of Afghanistan at a later time.

       However, in an update sent at 1.30am on Wednesday, the Defence Secretary tweeted: “Now that Pen Farthing’s staff have been cleared to come forward under LOTR [Leave outside the Immigration Rules] I have authorised MOD [Ministry of Defence] to facilitate their processing alongside all other eligible personnel.

       “At that stage, if he arrives with his animals we will seek a slot for his plane. If he does not have his animals with him he and his staff can board an RAF flight. I have been consistent all along, ensuring those most at risk are processed first and that the limiting factor has been flow THROUGH to airside NOT airplane capacity.”

       Animals will face four-month quarantine

       Mr Farthing has previously said the animals would be transported in the aircraft’s hold and that, once his staff were accommodated, any spare seats on the plane could be filled by other people cleared for passage by UK authorities, with the flight able to take 250 passengers in total.

       Defra officials have now helped facilitate kennels for the animals, which must undergo four months of quarantine should they make it to the UK due to the risk of foreign diseases including rabies.

       Campaigners involved in the rescue mission have also claimed that George Eustice, the Environment Secretary, had been helpful in ensuring the animals were able to come to the UK.

       The claims were not denied by Defra, although sources insisted that the priority was “biosecurity” and that contingency plans had been drawn up to ensure there were “adequate” spaces for the animals.

       On Wednesday, Dominic Dyer, an animal welfare campaigner who has helped promote Nowzad’s campaign, told The Telegraph that supporters had already been inundated with offers to adopt the animals when they arrived in the UK.

       He said there were currently “about 100 people” expressing interest in adopting a dog for every one available.