In June, I was happy, go-free and fit, running on the treadmill of the gym in a Stockholm hotel.

But by the second week in July, I was finding it increasingly difficult to walk the 10 minutes from my home in Bristol to my doctor's surgery. An invader was choking the breath out of me with every step.

My GP, Dr Nick Ring, examined me and listened while I told him that I'd also been coughing up a bit of blood.

"Pleurisy," he said, "but I think we'll send you for a chest X-ray to be on the safe side."

A few weeks later, I realised that I would never be on the safe side again.

The X-ray taken at Bristol Royal Infirmary showed a shapeless, milky, cloudy thing on or near my left lung.

Things moved fast after that.

I was booked in for a bronchoscopy, which is where they shove some tubes and stuff down your throat or nose and try to grab enough of the invader to give it a positive ID. For whatever reason, they couldn't get enough for a comprehensive diagnosis.

So then they had a go at a procedure called an aspiration, which is where they stick a longish needle into your back and attempt to collect some fluid from the lung.

This didn't work either, but I spent an entertaining hour in a reception area waiting to be X-rayed again and listening to the woes and wisdom of an elderly woman pensioner with bleak blue eyes in a wheelchair next to mine.

"You don't want to be too polite to this lot," she warned me, nodding at the circulating medical staff.

"Cos they'll keep you in, if you are."

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