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A plane chartered to rescue a former UK marine who founded an animal shelter in Afghanistan is expected to leave Luton Airport later on Thursday, against the backdrop of an escalating war of words between his supporters and the British government.
The process to repatriate Paul 'Pen' Farthing, his staff and animals was called Operation Ark and a supporter of the mission has funded the rescue plane.
While the aircraft is expected to land in the airport in Kabul on Friday, it remains unknown whether Mr Farthing and his menagerie will be waiting.
He revealed that his team have been outside the airport for more than 10 hours, unable to get through the Taliban blockade.
Taking to Twitter, Mr Farthing pleaded with Taliban representative Suhail Shaheen to provide "safe passage".
The Nowzad retinue of 69, including 25 staff and their relatives, have been told they are eligible to move to Britain.
The charity has received offers to adopt the 200 animals they are hoping to move to safety, but Operation Ark benefactor Dominic Dyer expressed his concern that the mission could be foiled if the Taliban did not relent.
"We are ready to go, we have a flight plan approved by the secretary of defence's office ... and we're ready to hit the runway at Kabul Airport on Friday morning to get Pen and his people off," the wildlife campaigner and broadcaster told the BBC.
"But they need to get into the airport ... we're going to have a plane on the runway and no one to rescue at this rate."
Another supporter of the campaign raised concerns that a "humanitarian disaster was brewing", tweeting footage believed to show one of the Nowzad animals having its thirst slaked by a water pump.
In a series of tweets Dr Iain McGill, whose bio states he is a veterinary surgeon, berated the UK government for not doing more to get Pen Farthing and the Nowzad team into the airport.
UK Defence Minister Ben Wallace on Thursday reacted scathingly to accusations of a dereliction of duty on his watch, after having been forced to deny his department was obstructing the Nowzad mission.
In a seven-tweet thread he accused Nowzad supporters of "unacceptable" bullying of Ministry of Defence personnel and rejected suggestions the Operation Ark flight had ever been blocked.
He did, however, reiterate his position that no one has the right to "queue jump".
Armed Forces Minister James Heappey waded into the dispute in an interview with Sky News.
"For [Mr Farthing] it is a grim reality of these situations that as a British national we would seek to expedite his passage into the airport but he, commendably, has said that is not what he wants to do.
"He is asking us, the Americans and the Taliban for safe passage but I am afraid safe passage is also other words for being brought to the front of the queue."
The minister said the UK government would not bow to the pressure only "because of the profile and the support [Mr Farthing] has".