The symptoms grew worse. By May 2020 it was very pronounced in my right hand. I was experiencing great fatigue as well as frequent graphic nightmares that involved acting out desperate struggles against wartime invaders. In my sleep I shouted and swore, hurled furniture about and sometimes attacked my wife, Liz. My handwriting had gone completely to pot, and I had largely lost the ability to take a note of the proceedings before me — an essential function for a judge. I was just short of 63 years old, which is a common age to get it, and it came totally out of the blue. Nobody in my family has had the condition. 

‘Dad, you really need to get that tremor checked out.” When my son Gregory said that to me on our summer holiday, I realised I could no longer ignore the shaking that had developed in my right hand. In October a neurologist raised the awful possibility of Parkinson’s.

By some miracle, this retired judge will fulfil his second ambition, to see Taylor Swift in concert

That month I had a scan. The report was blunt: “Appearances are most suggestive of idiopathic Parkinson’s disease or Parkinsonian syndrome.” I admit to a Jeremy Paxman-esque reaction: “F***!”

My glass-half-full personality softened the impact of the diagnosis but there is no denying the fear. The idea of ending up in a wheelchair in Shakespeare’s seventh age of man “sans teeth, sans eyes, sans taste, sans everything” is a prospect I can scarcely bring myself to contemplate.

A regimen of nine pills a day, large amounts of exercise and adjustments to my working pattern at first enabled me to carry on working. The main adjustment was that I was provided with a full-time judicial assistant, whose main jobs were to prepare a navigational guide to the case papers and to take a verbatim note of the proceedings in court.

Friday was my last day on the bench. I have decided to retire — nine years earlier than the statutory age limit of 75 — because I do not know how fast this condition will progress, or to what bodily or mental state it will take me. Even allowing for my Pollyanna-ish personality, I have to recognise that at some point, perhaps soon, I could well find myself seriously handicapped.

I therefore want to maximise my chances of at least a few good retirement years, and it is to try to bank them that I am going early. My ambition is to get my golf handicap down to a level that would allow me to play in the Parkinson’s Golf Open, which takes place annually at Celtic Manor near Newport, the site of the 2010 Ryder Cup. My second ambition was to see Taylor Swift in concert, and mirabile dictu (as we lawyers say) it has just come true. The daughter of a dear friend, who is a judge on the Minnesota court of appeals, has invited Liz and me to join her at Murrayfield in Edinburgh to watch the star next June. I am beyond excited but have wondered, having watched on TV the enormous crowds that she draws, how I will cope with the weak bladder with which most Parkies are cursed. Shake it Off should be adopted as the anthem of the global Parkinson’s community.

I still ski and ride my old horse Paddy. I play a lot of golf and tennis, poorly. I see my personal trainer, Luis Gonzalez, twice a week. I can do the plank for the entirety of Taylor’s Anti-Hero — that’s 3 minutes and 20 seconds. My trainer is convinced that anaerobic and isometric core exercises promote the natural generation of dopamine. (Parkinson’s is caused by a loss of nerve cells in the brain, leading to a reduction in dopamine, which has a critical role in physical movement.)

There is no Parkinson’s dividend. As Paxman says, the outlook is “f***ing awful”. The two of us have been doing a podcast, Movers and Shakers, which was my idea, with four other sufferers — Rory Cellan-Jones, Mark Mardell, Paul Mayhew- Archer and Gillian Lacey-Solymar. We started meeting regularly for a chat, a laugh and a moan in a pub, and the sharing made me understand that I was not alone; that my symptoms were not unique; that the diagnosis is not a death sentence; and that it is possible to lead a life that is better than tolerable.

The journey is different for every person with Parkinson’s. Someone once said that there are over a thousand ways in which symptoms can be manifested — and every person’s is different. Symptoms include a tremor, a slow and shuffling walk, depression, dementia and loss of the sense of smell.

About 30 per cent of sufferers do not have a tremor. This minority includes Jeremy, who is afflicted by postural instability, which leads to frequent falls. If you are already prone to depression, that symptom must aggravate the sense of despair incalculably.

A hero of mine is the late, great judge Sir David Penry-Davey. He was diagnosed with Parkinson’s in 2002 and retired early, in 2010, fearing that he would fall asleep on the bench (that being almost the worst transgression a judge can commit). By May 2015 he had been reduced by a gross tremor to utter wheelchair- bound helplessness, although amazingly, as I witnessed, he was still able to conquer the tremor for the few seconds it takes to smack a brilliant golf drive down the fairway. He was also a gifted pianist. His widow, Judy, told me that a few months later, after a week in bed with a flu-like infection, he got up, staggered to the living room and wobbled on his Zimmer frame over to the piano and played beautifully by ear for about 20 minutes, without a single tremor. He enjoyed a good supper, returned to bed and died of a heart attack that night.  

Although the disease ultimately defeated him, he looked it in the eye and gave it the finger right to the very end. He never uttered a word of self-pity and, as Judy told me, he always maintained that a sense of humour was the most important thing to preserve. That has become my mantra: preserve a sense of humour and have no self-pity.

Last month the cricketer Allan Border, 68, disclosed he had Parkinson’s. In an interview in The Australian he described how he had been told by a doctor friend that it would be a miracle if he made 80: “No way am I going to make another 100 — that’s for sure. I’ll just slip slowly into the west.” Well, I fully intend to take the attack to this unpleasant opponent and I regard 80 as a very attainable score. I hope and expect it to be higher. And I have absolutely no intention of slipping slowly into the west.

In April I attended what would be my final plenary meeting of the High Court judges presided over by the lord chief justice, Lord Burnett of Maldon, who was kind enough to refer to the podcast and said that increasing public awareness of the condition was “the best thing you’ve ever done, Nicholas”. Well, that’s very kind, I thought, but what about my 323 judgments?

At one of our meetings Rory asked: “Why would anyone want to listen to some decrepit old relics talking about living with PD?” To which Jeremy replied: “Because they might f***ing get it!”

Mostyn’s big cases

2003 Zeta v François Graff. At the time, the £10 million award to the model from a billionaire diamond heir was one of Britain’s most expensive divorce settlements. Mostyn called the win a “crushing victory”.

2006 Miller v Miller. A City asset manager with a fortune of £30 million was forced to hand over £5 million. Mostyn said the fact the couple were childless did not represent a diminished commitment.

2008 McCartney v Mills. The former model was awarded £24.3 million after demanding £125 million from the Beatles star. Mills was so furious she poured water over Fiona Shackleton, McCartney’s solicitor.