'I thought I was so lucky - then the wheels came off’

Betsy Duncan Smith talks for the first time about her battle with cancer, and how it inspired her to support a charity that uses dogs to detect the disease

I remember reaching 50 and thinking, 'goodness, life is good, I’m so lucky’ - and then, four months later, the wheels came off.” Betsy Duncan Smith, wife of the former Conservative Party leader Iain Duncan Smith, is speaking about her breast cancer diagnosis in 2009 and the gruelling treatment that consumed her life for the next two years.

“I’m not usually someone who goes around talking about my private life,” she warns at the start of our interview, and she is strongly averse to the limelight.

“People don’t know who I am,” adds the woman who, had fate played out differently, might have ended up in 10 Downing Street in place of Cherie Blair, “and I’m quite happy with that.”

Indeed, there is only one reason she has agreed to talk publicly for the first time about her ordeal, and that is her strong belief in the “mind-blowing” potential of cancer-detection dogs. She is a trustee of Medical Detection Dogs (MDD), one of the charities supported by theTelegraph’s Christmas Charity Appeal, which runs to the end of January. The former Elizabeth Fremantle, daughter of the fifth Baron Cottesloe, lives with her husband on her family’s estate near to the charity’s Buckinghamshire headquarters, which is how she became involved.

“A friend asked me in 2012 to come along and see what the charity did,” she says. “I was pretty reluctant. I had just had breast cancer, and had a rough time for two years with the treatment. So the last thing I wanted at that point was to get involved with anything concerning cancer.”

The charity trains medical alert dogs – able, for instance, to detect by smell changes in blood sugar levels in their diabetic owners. But MDD is also a world-leader in ongoing research that uses dogs to sniff out evidence of cancer from batches of breath or urine samples, often before symptoms have manifested themselves. It was that connection between the pioneering work in the early detection of cancer and her own experience of the disease that inspired Duncan Smith to go along. “When I was finally persuaded to visit, I was quite simply blown away,” she says.

What floored her during her own treatment, she recalls, was a serious reaction to chemotherapy. “My energy levels went to zero. There were days I just couldn’t walk. On occasion I couldn’t even talk. Iain had to bring his office home and look after me. It must have been very worrying for him, poor chap, but he coped brilliantly.”

Especially since, in the middle of it all, he had a general election campaign to fight in 2010. It was Betsy’s husband who first revealed her cancer diagnosis in a newspaper interview around that time – briefly, making it clear he didn’t want to go into detail, but adding that when she rang him with the news, “it took my breath away”. Colleagues at the time reported him as tearful in private whenever the subject was raised.

The picture she paints of her husband’s unflagging domestic solicitousness throughout her illness contrasts with the accusation often heard that, in overhauling the benefits systems, the Secretary of State for Work and Pensions has shown himself both uncaring and temperamentally detached. Inevitable comparisons between the public and the private man are probably one reason why his wife has kept such a low profile.

“My cancer was found very late. I didn’t pick up any of the signs,” Duncan Smith says. The founder of MDD, psychologist Dr Claire Guest, had her own breast cancer detected early by her labrador, Daisy, who started repeatedly nuzzling the affected area; that prompted Dr Guest to examine her breasts, which is when she found the lump.

Did Duncan Smith’s own dogs alert her? “No,” she replies, “though I suspect they tried to, but I just didn’t read the signs. At the time of my diagnosis, we had a collie and a spaniel, who might have been trying to tell me, but I didn’t notice. I was rushing around. You don’t stop to think. I just didn’t think about cancer.”

The charity is now running proof-of-principle trials to demonstrate how its dogs can detect cancers. Current training and testing data shows that at least one of the MDD dogs has a success rate of 93 per cent, and no dog is used who has a “false-positive” rate of more than five per cent – that is to say they mistakenly identify more than five per cent of samples as having cancer.

After diagnosis, Duncan Smith had six months of chemotherapy, followed by radiotherapy. “I didn’t have such a bad reaction to the latter,” she recalls. “I was determined to drive myself to and from the hospital. People very kindly said that they would drive me, but I’d become so dependent. I was lucky because Rosie, my youngest [of four, two boys and two girls], was 16 at the time. Ten years before, if I’d had breast cancer, I don’t know how I would have looked after my family.

“Breast cancer just took over my life for two years. The first bit was the worst. I couldn’t see a way out of it, I was being so ill. I was just getting through every day.”

As a side-effect of treatment, she lost her hair. “That didn’t bother me in the slightest,” she says. “It was the least of my problems. Eventually, though, I started getting stronger. I’m out of it now but I’m still regularly checked.”

Her energy levels have certainly bounced back. Being a trustee of a charity can sometimes involve little more than attending a quarterly board meeting, but Duncan Smith’s commitment to MDD goes much further. The day after our interview, she was involved in a presentation to a large bank that might offer sponsorship.

She is also a member of the MDD delegation meeting the All-Party Parliamentary Group on Cancer, hoping to push the potential of the dogs to aid the current drive to improve rates of early detection of the disease.

“It’s blindingly obvious that we have something here,” she says. “Our dogs are the best machine in the business. They can beat any cancer detection device, and they are so much cheaper.”

And less intrusive than, say, a mammogram? “Yes, of course, but at the moment with breast cancer, there are two people checking every test. Why not involve dogs as well? Let them have a secondary role in screening. It takes them less than a minute to screen eight samples.

“What I really want to do is urge people to forget that dogs are wet noses and waggy tails and focus instead on the science,” she says. “These dogs’ sense of smell is so strong that, in trials, they can detect traces of amyl acetate when it is diluted in the ratio of one part to a trillion. That is phenomenal and certainly shows you the potential. It’s the equivalent of one drop in two Olympic swimming pools.”

Once engaged, it seems, Duncan Smith is a fierce campaigner. This quiet woman is not – to quote her husband’s famous 2002 conference speech as Tory leader – to be underestimated. Neatly dressed in a tailored oatmeal tweed jacket and black trousers, she describes herself as, by inclination, a country girl, never happier than slopping around in a pair of jeans and away from the crowds.

Did the prospect of ending up in Number 10 cause her to change her image? “Well,” she laughs, visibly growing more relaxed, “I’ve had to learn to tidy myself up.”

Many of the 18 dogs being used in MDD’s clinical trials are cocker spaniels, a breed especially well-suited to the task. The Duncan Smiths now foster one of them, Jobi, a lively black cocker, who (like all MDD dogs) lives “out” with the family.

This, then, is very much her cause – though she does point out that her husband is right behind her. “Iain helps, too, because he’s on a three-line whip,’’ she says wryly.

During her two years involved with MDD she has witnessed a shift in attitudes. “At first the medical people weren’t interested. Claire [Guest] nearly closed down the whole cancer side of the charity because people weren’t listening and concentrated instead on medical alert dogs [for those with conditions such as diabetes]. I think some medical professionals just thought it was another mad-dog charity, but now that is changing.” Two local NHS trusts have joined forces with MDD to carry out the current trials.

Her principal role, though, is to “drag people in”. “If I do find myself sitting next to someone at a dinner that I think can help, I babble on to them about MDD. If I can get them to come down, as soon as they’re through the door, they are caught.” Being married to a senior Cabinet minister no doubt gives her rare access to influential ears to bend. She is unapologetic.

“NHS England has just announced a new push on early detection of cancer, and I want to say to them, don’t write us off. Let our dogs be part of your work. Dogs are used to save lives elsewhere – at airports, around explosives, even checking out the House of Commons. Why this reluctance to use them in medicine?”

If this persuasive woman has her way, such reluctance will soon be a thing of the past.