I HAVE a zero immune system so the smallest scratch or minor cough can turn into blood poisoning or pneumonia. My biggest danger area is a crowd and both Christmas and New Year bring their own crowds

I pole-vaulted from an isolation bed in the Churchill Hospital to the middle of holiday crowds in a matter of days, probably because I’m my own worst enemy. It’s not that I don’t know any better; I’ve had plenty examples of ‘good practice’.

A friend with a tumour down her back was not supposed to survive her cancer, but during her treatment she went into self-imposed exile. She avoided crowds by going to out-of-town supermarkets at off-peak hours to avoid people and refused to allow even close friends into her house if they were not in robust health. In particular she wouldn’t let any grandparents visit her because their small children tend to collect germs which could be incubating in any unsuspecting, cuddly grandparent.

She even made her family undergo quarantine treatment. When her only son came to visit for lunch while one of his office co-workers had the flu, she forced him to eat lunch with her outside sitting side by side in her garden during February dressed in overcoats, hats, gloves and mouth masks, which must have made eating a bit of a chore.

She disinfected her whole house which was an old stone barn conversion and kept one special chair constantly sprayed with a special solution to protect her against germs. This was her ‘throne’ and nobody else could use it.

Hats off to her, she’s still surviving some time later, but that wasn’t my way. It’s hard to change the habits of a lifetime. As a child I was always the last one out of the sandbox and covered with dirt. Germs must be in the genes because my son, Magnus, at sandbox age managed to crawl on to the kitchen table where we kept the bread and butter and he opened the butter dish and smeared it all over himself, even his hair.

My two stepdaughters took a more militant view. Harriet and Livvy decided to de-germ the house as soon as they heard I was diagnosed with leukaemia. When they found out the consultant advised I should live in a squeaky clean environment they gasped and thought that was an even bigger challenge than the leukaemia.

They put their own lives ‘on hold’ and spent 14 hours per day for 10 days to transform the house. Without warning they took everything at home which included 30 years of collecting precious items, at least ‘precious’ to me, and dumped them in one pile to be sorted out later. So all the Egyptian relics and Peruvian weavings together with boxes of the 21 pills I have to take each day ended up in what became one huge garbage bin formerly known as our sitting room.

I was shocked and asked them what they were doing. With a straight face Livvy calmly replied: “I’m really going for gold on the mould.”

Fine…but when your mental world is turned upside down by a diagnosis of cancer, when all the furniture of your mind which you relied on melts away and then everything in your physical world is turned upside down on a rubbish heap it’s a left hook to the jaw and a right punch to the body of your self-image.

The kids said that cleaning the house for me was like looking after a toddler. I didn’t have a clue about limiting contact. Even now after months of treatment when a house guest arrived for the festive celebrations I shook hands and started to talk with him without a second thought that this might be a menace. He had come by London Transport where the only place to sit or stand is where thousands of other people have been doing the same thing. It’s probably one of the biggest bug-breeding machines in London. Shortly after he arrived we both had to hold out our hands for a spray of the hand sanitizer.

And this is my problem. All the signs are there – Don’t touch! Stand back! Play it safe! – and despite the warnings, I don’t. I hold hands, touch, hug and kiss. I take risks and do all the wrong things. So, on the form where it says ‘cause of death’ finding the answer will be easy.