John Pritchard Williams was a consultant urological surgeon to St Peter’s Hospital, Greenwich District Hospital and King Edward VII’s Hospital for Officers in London. He was also an honorary consultant urologist to the Army. ‘JP’, as he was always known to friends and colleagues, was born on St Valentine’s Day 1926, the elder of twins. His father, John Pritchard Williams, was a successful surveyor; his mother was Dorothy Williams née Bates. Brought up in Sheen, west London, he was educated at the Leys School in Cambridge, where he became head of his house, going on to win a place to study medicine at Emmanuel College, University of Cambridge. He subsequently completed his clinical training at St Mary’s Hospital in London, qualifying in 1950. His first house job at St Mary’s was as a house surgeon to Sir Arthur Porritt. This was followed by further junior posts in the hospital, during which he met his future wife Patricia Freeman (‘Pat’), a St Mary’s nurse. They married in 1952, just before he commenced his National Service in the Far East as a surgeon lieutenant commander on the aircraft carrier HMS *Unicorn* and then on the frigate HMS *Alert*. He returned to surgical registrar posts in London, before being appointed to a four-year senior registrar rotation at St Mary’s in 1957. He became a fellow of the Royal College of Surgeons of England in 1956 and gained his MChir in 1958. In 1960 he spent a year as a research fellow at Harvard Medical School, before returning to St Mary’s as a senior registrar to Sir Arthur Porritt. In order to gain further experience in urological surgery, he applied for and was successful in gaining a resident surgical officer post in the St Peter’s Group of Hospitals in Covent Garden, where the Institute of Urology of London University was based. He subsequently became a senior lecturer and sub dean there and, in 1968, was appointed to the consultant staff of St Peter’s and at Greenwich District Hospital. With beds at St Paul’s Hospital, he developed an interest in the diagnosis and treatment of prostatic carcinoma, publishing on the use of the Franzen needle technique for aspirating cells from prostatic tumours for cytological analysis. He also espoused the use of pituitary ablation by the implantation of radioactive yttrium seeds under X-ray control as a pain relief treatment for advanced disease. Other papers followed on pelvic lymphadenectomy and urinary incontinence. As his career advanced, he became deeply involved with the British Association of Urological Surgeons, serving on its council between 1971 and 1978, when he was the honorary secretary, with sporadic *ex officio* membership until 1990. With John Blandy he published a history of the Association (*The history of the British Association of Urological Surgeons, 1945-1995* London, The British Association of Urological Surgeons, 1995). During this period, he also became a member of the court of examiners of the Royal College of Surgeons of England and joined the list of honorary consultant surgeons to St Luke’s Hospital for the Clergy. He was a fellow of the Royal Society of Medicine, where he was on the council of the section of urology, serving as president of the section between 1989 and 1990, when he arranged a memorable winter scientific meeting in Courcheval, France, where a lack of snow failed to limit the success of the occasion. JP’s affection for the Navy never left him and throughout his life he retained a certain nautical style. He was an accomplished yachtsman, owning a number of boats with colleagues. His juniors all recall invigorating maritime experiences when, as extra hands, they accompanied him on eventful cross channel cruises. Widely respected by his juniors as much for his geniality, kindness and interest in their future careers as for his surgical technique, he repaid their respect by inventing the Chrysalis Club at the Institute of Urology, a popular monthly meeting where generations of urological trainees from London hospitals gathered to present and discuss problematic clinical cases in a relaxed and informal manner. On his retirement from the NHS at the age of 65 he continued with his busy private practice, remaining as a consultant to the King Edward VII’s Hospital for Officers, to which he had been appointed in 1977. His consulting rooms contained a spinet, which he would play between appointments. Even at a very considerable age he continued to play the piano and, after retiring to Milland in West Sussex, was often seen playing in village reviews and concerts. There were many trips to London to call in to the Garrick Club, to play real tennis at Lords or to occupy his seat in the pavilion to watch test matches. He resurrected an interest in archery and invested in a long bow, which visitors were invited to draw. After the death of his beloved wife Pat in 2015 his health slowly deteriorated and, in 2019, he transferred to a care home in Hindhead, Surrey, where his life drew quietly to a close on 16 February 2020, two days after his 94th birthday. He was survived by his daughter Clare, a banker, and his son Hugh (the actor Hugh Bonneville). Another son Nigel had died in 2017.