I beg you, Carrie, woman to woman... help save Geronimo: As her beloved alpaca awaits the executioner at any moment, vet's nurse makes last-ditch plea to the one animal lover she prays can help – Boris Johnson's wife

It's the story that has captured the nation's heart — the alpaca sentenced to death after testing positive for bovine tuberculosis on his arrival in the UK four years ago, now set to be put down within days.

More than 80,000 have signed a petition to save Geronimo the alpaca after his owner Helen MacDonald lost a court battle to stop his death.

She claims the blood tests that sealed his fate are flawed. And now the Mail can reveal that government officials knew about problems with the tests five years ago but would not investigate. 

In spite of this, they have refused to re-test the animal — which has not had a test since 2017.

Despite these revelations, last night Boris Johnson's official spokesman reiterated that there were no plans for further tests to be carried out.

However, in an impassioned plea, here Helen MacDonald makes a last-ditch appeal to the one person who may still be able to change the Prime Minister's mind, and save Geronimo's life...

The paddocks surrounding Helen MacDonald's Gloucestershire farm may seem like an unlikely venue for a western-style stand-off. Alpacas graze contentedly on the lush grass, and only birdsong interrupts the pervading peace.

But any official person who dares to visit in the coming hours and days will be in for a shock.

'I will do whatever it takes,' says Helen. 'And if that means taking a bullet then I will. I will simply not be bullied.'

They are strong words, but then Helen has been battling passionately for four years and quite simply is at the end of her tether.

Her fight centres on the future of her eight-year-old chocolate alpaca, Geronimo. 'It's not about just him but about what's right,' says Helen.

More than 80,000 have signed a petition to save Geronimo the alpaca after his owner Helen MacDonald (both pictured) lost a court battle to stop his death

Geronimo has been earmarked for execution by government agencies ever since his arrival in the UK four years ago, after twice testing positive for bovine tuberculosis . 

But Helen has now reached the end of the legal road. Last week, a High Court judge issued a fresh warrant for access to her property to enable an execution.

Veterinary nurse Helen, 50, believes those tests to be categorically wrong and has dedicated her life to trying to prove it. 

And, today, desperate to stop her beloved Geronimo falling victim to execution, she makes an impassioned plea to the Prime Minister's wife, Carrie Johnson, to save him.

'I am appealing to Carrie directly to ask the Prime Minister to intervene. She is a patron of the Conservative Animal Welfare Association and has campaigned for the environment and the welfare of animals. 

'As an animal lover, surely she cannot stand by and let this happen? I am begging her woman to woman to do what she can.

'She and Boris have a beautiful dog, Dilyn, who they clearly adore. I feel about Geronimo exactly the way they feel about him. Please Carrie, help Geronimo. He really does not deserve to die.' 

Carrie has been fearless with her campaign for animal rights, leading Peta (People for the Ethical Treatment of Animals) to last year name her 'person of the year'.

In January, it emerged that Carrie had been hired as head of communications by the conservation organisation the Aspinall Foundation, known for its work protecting endangered species.

Moreover, just last month, the Conservative Animal Welfare Association, of which she is a supporter, called for ministers to broaden the scope of its Animal Welfare bill to include crustaceans, stopping the practice of restaurants boiling lobsters alive.

In an impassioned plea, Helen MacDonald has made a last-ditch appeal to animal lover Carrie Johnson , the one person who may still be able to save Geronimo's life

'If she can lend her voice to the protection of lobsters, then surely Carrie can intervene to stop a healthy alpaca being shot?' says Helen.

With no further legal recourse, it leaves Helen in a terrible dilemma: with the warrant valid for 30 days from last Thursday, she is expected to either arrange with her vet for the euthanasia of an animal she claims is healthy, or wait for a team to turn up and shoot him.

'I genuinely think that when I lost in court last week the officials thought that I would come home, put him down, and we'd all get on with our lives — but I'm just not prepared to do that. How can I ring my vet and ask him to kill a healthy animal I love?' she says.

'Equally, the team from the Animal and Plant Health Agency could turn up at any 'reasonable hour' apparently. I don't know what the definition of that is, but they can bring the police, force their way in, and shoot Geronimo. And that's horrific.'

Adding to her distress, yesterday police officers arrived at Helen's farm shortly after 5pm. 

They told her they wanted to make themselves known as, in accordance with the High Court warrant, they would be accompanying any Defra vets onto the farm so that contractors can kill Geronimo.

'The police were gauging the level of resistance they might face if and when they arrive with the vets,' says Helen. 'It's very upsetting.'

Her plight has certainly captured the imagination of the country; Helen has been inundated with messages of support and a petition to save Geronimo has almost 80,000 signatures. 

Celebrities have joined in the chorus, with Joanna Lumley and Chris Packham voicing their dismay at the prospect of what Helen has labelled a government-appointed slaughter.

When we speak at her farm in Wickwar, Gloucestershire, her emotions are clearly raw; her eyes brimming with tears.

'It's hugely stressful and has been for years,' she says. 'The constant fighting and the anxiety is debilitating. My whole life has been taken over by it.'

'The government have a mission for disease control, I get that, but it's not right to make stuff up, to make your policy fit the situation.

'Geronimo doesn't have bTB, and they know it. We have shown he did not catch bTB in New Zealand, as suggested by officials.'

At least Geronimo is unaware of his fate. Now in his prime, Helen brought him to breed from, but courtesy of his diagnosis he has spent every day here in the UK segregated from Helen's herd.

Helen's love affair with alpacas began nearly 20 years ago, when she attended a country show.

Single and looking for a diversion, in 2002 she decided that she wanted to set up her own breeding herd. 

'I visited half a dozen different sites,' she recalls. 'After that I bought my first three females.'

Costing £10,000, Ebony, Fluffy and Cheeky were the first trio in a herd that today numbers 80, a small slice of the roughly 45,000 that are now registered in the UK.

Over time, she moved to her own farm. Today, she should be making the farm pay for itself by selling breeding stock — but she can't, as the government's agricultural department, Defra, have slapped a movement ban on her livestock given Geronimo's 'diagnosis', meaning the loss of an estimated £80,000 profit in the past four years.

Geronimo arrived four years ago from his native New Zealand when Helen decided to introduce a new bloodline to improve her herd and was put in touch with a breeder there via a friend. 

Geronimo (pictured with Helen) was sentenced to death after testing positive for bovine tuberculosis on his arrival in the UK four years ago and is set to be put down within days

He arrived in the UK on August 10, flown by cargo plane by an importer with 28 other alpacas at a cost of £10,000.

Although Geronimo had tested negative for bTB before he left, Helen decided to give him a different and newer voluntary blood test, administered by an external government approved agency.

'It was one we could do to show that our herd was healthy, so we could trade successfully. My whole herd had already been tested with it the year before, and I was trying to promote the test to industry as a good idea. Except it backfired spectacularly, didn't it?' she says.

It certainly did: a few days after the test, Helen found her elderly mum, with whom she shares her farm, sobbing.

'She said APHA had telephoned and said that Geronimo has bTB and had to be culled,' she recalls.

It was the start of nothing short of a legal and ethical nightmare. Helen believes Geronimo gave a 'false positive' test result because he had been 'primed', meaning he had already been injected with a small amount of bovine tuberculosis as a way of gauging immune response. 

It meant that a subsequent test enforced with more tuberculin four months later, produced a similar positive.

'Defra are aware of the evidence linking alpacas who have had skin tests becoming positive on this test, and no research has been done,' Helen says.

And so, in essence, her fight since then has been to ask for another straightforward blood test — with no prior 'priming'.

'We've been asking for that for four years, but they won't do it because they don't have to,' she says.

Her fears about the tests, and that Defra have long been aware of the issues surrounding them, are backed up by minutes of a meeting between Defra and the British Alpaca Society in April 2016 — revealed by the Mail today — which show government officials knew about problems with the tests five years ago but would not investigate.

'The evidence is really strong that these tests are flawed. Those minutes are key to showing Defra have prior knowledge of the problems with the tests but they have chosen to ignore it,' says Helen.

'They've known since 2016 that those tests produce false positives if you give an alpaca more than two shots of tuberculin within a 12-month period.

'Environment George Eustice claims the tests are 'highly specific' but that is bunkum.' 

Helen claims that 'when Geronimo tested positive Defra changed the goalposts so that two antigen spots instead of four were enough to show a positive result.' 

She believes 'it is inconvenient for them to know that priming is causing problems with the testing process.'

According to minutes of a meeting between Defra and the British Alpaca Society, in April 2016, government officials acknowledged that the skin tests used on imported alpacas had the potential to cause false positives in subsequent blood tests.

The meeting was told that alpaca owners and breeders were concerned that repeated skin tests, which involve animals being injected or 'primed' with tuberculin — a substance that promotes an immune response — could cause a build-up of tuberculin and lead to alpacas falsely testing positive for bTB in later blood tests.

The officials resolved to take skin tests into account when deciding whether a positive could be false — but this does not seem to have happened for Geronimo, who was primed with three lots of tuberculin after undergoing three skin tests in 14 months, between September 2016 and November 2017.

Duncan Pullar, chief executive of the British Alpaca Society, said the organisation had offered to 'financially support' Defra to investigate problems with tests, but they had refused.

A Defra spokesman insisted the tests used for Geronimo were 'highly specific' and that they did not expect false positives to be shown.

When appealing the test results Helen's first port of call was the then Secretary of State for the Environment, Michael Gove, for Geronimo to be retested. 

Helen (pictured with Geronimo) claims the blood tests that sealed his fate are flawed, but government officials have refused to re-test the animal - which has not had a test since 2017

His refusal led her to court, when she successfully applied for a judicial review of APHA's decision, only for a High Court judge to throw out her application on the basis that the decision to euthanise Geronimo wasn't 'unlawful' or 'irrational'.

'They did concede that Geronimo may not be infected,' she says.

From there Helen went first to the Court of Appeal, only to have her application thrown out, an endeavour repeated by the European Court of Human Rights.

She wrote a letter to the new Secretary of State for Food Environment and Rural Affairs, Theresa Villiers, and many to her successor, George Eustice.

For a while things went quiet, until December last year, when out of the blue Helen got an email informing her that the local Magistrates Court were to hold a Warrant hearing — effectively issuing Geronimo's final death notice.

Her most recent plea for a reprieve was finally rejected at the end of last month by High Court judge Mr Justice Griffiths, who said there was a need to protect against the 'serious consequences' of the disease. 

Within hours, Helen had received a phone call from her case officer asking when Geronimo's carcass could be collected.

'These people just rely on you giving up, but my mindset won't allow it,' she says.

Nonetheless, there is no getting away from the fact that legally, Helen is out of options.

She has spent the last few days making further phone calls and sending emails to ministers and Christine Middlemiss, the UK's Chief Veterinary Officer, asking for them to intervene — to no avail.

'At the heart of it I am saying that you cannot execute an animal when there are documented question marks over test performance and admitted deviations in protocol — you shouldn't be able do this without evidence-based science,' she says. 

'This is not just about Geronimo but has massive implications for other animals, too.'

Whatever the events of the next tense few days, it would be a hard-hearted soul who did not wish Helen — and Geronimo — luck. At the moment of writing, she still doesn't know what will happen.

'I can't really bear to think about it and the thought of this going on for days is horrendous,' she says. 

'My family is very worried about what's going to happen to me. But all I can think about at the moment is Geronimo.'