Supporters of a former Royal Marine attempting to evacuate 200 animals and his staff from Afghanistan have called on the Foreign Office to “rubberstamp” the rescue operation.

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

Since the collapse of the Afghan government, he has been campaigning to have all his staff and their families, as well as 140 dogs and 60 cats, evacuated from the country in a plan he has dubbed Operation Ark.

On Monday, a jubilant Mr Farthing announced the UK Government had granted visas for all his staff and their dependants, but supporters suggested he needed approval from the Foreign Office before they could leave.

Veterinary surgeon Dr Iain McGill said a privately chartered Airbus A330 – funded by donations – was on standby to fly to Kabul to rescue the group.

“We’ve been working behind the scenes and the Prime Minister has approved it, Defra has approved it, the veterinary profession has all signed off on it, and there are people ready and waiting to take the animals,” Dr McGill told the PA news agency.

“The Home Office have approved it and it is just the Foreign Office. Once the Foreign Office rubberstamp it and get it to Pen, he’s in the airport within hours.

“Pen has got transport for all the staff and animals and himself safely to the airport. They just need that document to show to the military so they will let them in.

“In the airport they can wait for a few days until the plane arrives, they just need to get safe. Pen doesn’t have that long a window because of the military operation.”

Dr McGill added: “If I was speaking to (Foreign Secretary) Dominic Raab now, I’d say that I realise there are a lot of issues in Kabul and there has been difficulty getting enough flights out.

“If we can just get this document signed off for these 68 people to Pen then he can get into the airport and that will be the matter resolved for them and no more bad publicity and this will go away.

“It will be a good news story and millions of people will be pleased, who have supported him, and sent money.”

Dr McGill said that after the animals and the charity’s staff, the remaining 130 seats on the plane would be filled with at-risk Afghans.

Frankly I have to prioritise people at the moment over pets

Earlier, Defence Secretary Ben Wallace said Mr Farthing could leave Afghanistan as he was a British passport holder and urged him to do so.

“As for the animals that he has rescued and saved, it is just not going to be the case that I will prioritise them over the men, women and children we see in desperate need at the gate,” he told Sky News.

“I regret that, but I don’t believe that the Taliban’s main point of target will be his workforce and indeed the pets and the animals he is looking after compared to some of those other people desperate in front of the queue.

“Frankly, my day job, and my evening job, and my night job, is focusing on those thousands of people outside the front gate.

“He’s been offered a place, last Friday, he was called forward. I strongly recommend he does that.

“And once the evacuation is over I genuinely believe that his workforce, and if he wants to repatriate the pets that he looks after and the strays, I genuinely believe that they will be allowed to move forward at a later date when that airport opens.

“But frankly I have to prioritise people at the moment over pets.”

Mr Wallace said if an aircraft flew in on Tuesday to pick up Mr Farthing, his staff and animals, it would block the airfield and sit there empty.

“There is a confusion and I think I’m afraid some of the campaigners have latched on to the fact they’ve chartered a plane that this somehow is the magic wand,” he added.