"I was invited this weekend to the south coast so I could go swimming," he wrote. "Swimming? In the English Channel? I'm off the fags, for Christ's sake. I haven't gone mad. Swimming in British waters is something you should consider only if your Spitfire's been shot down."
He advised others trying to quit to go places where it's near-impossible to smoke, like the cinema, or Australia, where cigarettes are highly priced and banned in many public spaces.
He said that it's helpful to have a friend willing to quit with you, and the key to staying away from the cigarettes is "willpower".
"So now it's been a month. I've pushed it. I've got drunk. I've stayed up late. I've been to bars with smokers and sat outside in a cloud of their exhalations. And so far I haven't cracked,' he wrote in his column.
After his bout of pneumonia, Clarkson said lung tests showed he still had 96 per cent capacity for a person his age and he could "breathe out harder and for longer than a non-smoking 40-year-old".
"In short, getting on for three-quarters of a million fags have not harmed me in any way. I have quite literally defied medical science," he wrote.
Clarkson fell ill earlier this month while on the Spanish island of Majorca and has opened up about his time in hospital in his Sunday Times column.
He wrote that he had spent "three nights spent spasming in my bed" before a doctor sent him for tests at the hospital.
He was then told he would have to be admitted "for at least a week", which he called "impossible".
The doctor added: "If you don't do as I say you will die," writes Clarkson.
The TV presenter described his boredom in the hospital as "so bad I thought often about killing myself".
He writes: "I'm sure many of you will have found yourself in hospital, not having planned to be there.
"But for me it was a new experience. And a weird one. Because I was in a room with nothing on the walls except wallpaper, and most of that was coming off."
The outspoken TV personality has now left hospital, but faces two months of recuperation.
He added: "This is the problem with hospitals. People who stay in them become institutionalised and incapable of speaking about anything other than what nurse brought what drug at what time.
"Boredom turns them into bores. And when they get out, as I have, and there is nothing to do for two whole months apart from get better, things are even worse, because all I can talk about is my illness."
Clarkson announced news of his illness earlier this month, posting on Drive Tribe he would be "out of action for quite some time ... It's really really annoying because I've never had one day off work since I started in 1978," he added.
The illness comes two months after his co-host Richard Hammond was airlifted to hospital when his car crashed while filming The Grand Tour.
In December 2014, Clarkson admitted that he had let himself go and put on "a lot" of weight - and that a doctor had branded his fitness level as "atrocious".
The presenter, who regularly makes headlines for his on-air remarks, spoke on The Chris Evans Breakfast Show.
During the interview, it was pointed out to him that, even with his usual paunch, he appeared to have to be "a bit" fatter on a Top Gear DVD that had just been released at the time.
Clarkson immediately corrected TV-turned-radio presenter Chris Evans, saying: "Not a bit - a lot fatter."
Describing his ample stomach as "the product of hard work", he added: "I eat a lot but mostly I've cultivated it by sitting down all the time. Literally all the time, I'm now exhausted.
"Getting to your studio this morning I had to have a 15-minute rest." He added: "I had to go for a medical the other week. They put me on a treadmill and described my fitness as atrocious."
The father-of-three has previously painted himself as a man unable to shy away from indulgence.
He has claimed he cannot write his scripts without ample supplies of alcohol, cigarettes and caffeine, adding: "The amount you drink when you're writing, that's the thing that worries me."
And in a newspaper column back in 2014, he wrote: "I get tired pulling on my socks these days. So, if I want to live much past the end of next weekend [my doctor] says I must give up smoking, drink less, walk more, lose weight.
But in typical nonchalant style, he said of his role on Top Gear: "If somebody decides one day that actually you really have got too fat or you really are awful then you do something else."
