From the mid-Fifties, he was Chief Rocket Development Engineer in charge of Black Knight, Britain's first rocket programme. He planned and implemented the building of the testing station, as well as the rocket, which in a typically uncompromising way, he sited on a cliff edge towering above the Needles on the Isle of Wight.
First launched in 1958, at Woomera in Australia, Black Knight captured the headlines and British newspapers hailed the achievement as remarkable for costing just pounds 50m, only to have to set the record straight a few days later when it was confirmed that the budget was actually a mere pounds 5m.
In the late 1950s, the United States were struggling to make their space rockets work properly. The fact that Black Knight was the first rocket of any nation to operate successfully on its first launch and to budget led to a Daily Mail cartoon of the time showing Harold Macmillan, dressed as a medieval knight in a black suit of armour, walking into a meeting of US space chiefs, surrounded by pictures of failed rocket launches, to offer his help.
Leyton was born in Leeds in 1914, but was brought up on the Isle of Wight. He was educated at Kingswood School in Bath, then joined Austin Motors in 1931 as an apprentice. He worked as a teacher for a few years, and during the Second World War served in the RAF, then the Air Branch of the Royal Navy. With the engineering experience he gained during his war service, he worked in various engineering jobs until in 1956 he joined Saunders Roe to work on the Black Knight project.
Encouraged by the success of Black Knight, Leyton wanted to press ahead and held realistic ambitions for a British orbital rocket, but the Government were less eager to continue and so he resigned.
He moved into the commercial business sector as Engineering Director of Black & Decker from 1959 to 1961, but his next step soon came when, looking to opt out of the rat-race, he decided to buy a country pub. He found a hostelry in Somerset called the Miners' Arms, in Priddy, which gave the newspapers the ideal opportunity for headlines such as "Countdown gentlemen, please".
However, his new pub wasn't even a pub, but an unremarkable restaurant that had lost its pub licence over half a century earlier. Despite neither Leyton nor his wife having any catering training or experience, the Miners' Arms was soon voted one of the most interesting restaurants in the UK by Raymond Postgate and featured in The Good Food Guide and Egon Ronay's Guide.
Always on the lookout for the unusual, Leyton discovered that snails, known locally in the Mendips as wallfish, had been a low-cost dish on the menu of the local mineworkers up to a century earlier. Unheard of in the UK at the time, snails were domesticated and anglicised by Leyton with the creation of a snail sauce based entirely on local ingredients, with no garlic.
Leyton's engineering background still shone through in the world of catering: first, with the design of an electric fence to keep up to 100,000 snails at a time in a disused swimming pool; and then, with the introduction of the freezing of prepared snails and other complete dishes. This led to considerable debate in gastronomic circles at a time when freezing was only considered suitable for basic ingredients. Egon Ronay himself was provoked into writing to The Times expressing his doubt over such practices whilst acknowledging that "Mr Leyton is a unique exception, because of his scientific background and his individual perfectionist attention to the process of cooking and freezing".
Further exploiting his technical knowledge, Leyton developed an insulated container that would keep food frozen for days, followed by a patented "Leyton Tempstick" that indicated if food had ever exceeded a safe temperature. The two inventions allowed him an early entry into the food mail-order business.
Constantly searching for new ideas to introduce into the restaurant, in 1973 he started brewing his own ale and the Miners' Arms became the smallest licensed brewery in the country. The growing reputation of the pub saw an increasing clientele which included Egon Ronay, Delia Smith, Terry Wogan, Kate Adie, Malcolm MacDowell, Anthony Hopkins and Lord Sieff of Brimpton.
Leyton made a number of appearances on radio, as an expert on snails, and, shortly before he left the Miners' Arms, the BBC devoted a programme to him under the title A Man of Independent Mind.
When he retired at the age of 63, Leyton still wanted to do things his way and he moved into a modern mobile home which became his and his wife's home for the next year whilst they toured the country looking up old friends and caring for disused National Trust properties on the way.
This was a return to his lifestyle of almost 30 years earlier when, in 1948, he had purchased a double-decker bus and spent six months converting it into a mobile home. Complete with Aga for cooking and heating as well as hot running water, the bus served as a home for him, his wife and their first three sons for almost five years and was featured in Picture Post.
When they had tired of travelling Britain in their mobile home, Paul and Nancy Leyton returned to the Isle of Wight, where they had grown up as next-door neighbours. Leyton's spirit of adventure did not desert him even in retirement. They moved into a little cottage overlooking the Channel, with no mains water, electricity, gas or drainage. Leyton then designed and built a series of windmills to recharge a bank of batteries that served as the only means of power in the house.
He served as a local councillor on the Isle of Wight for a number of years, devoting much of his time to studying, analysing and reporting on the rapid erosion of areas of the south-west coast of the island. He was able to devote more of his time to his lifelong passion for writing poetry and piano music. Much of his work had an amiable irreverence to it, typified by the "Lion Song" written for the Marquess of Bath, a regular customer of the Miners' Arms, which is today stored in the Old Library at Longleat. Leyton also helped in the initial design of the fencing at Longleat when the lions first arrived.
When in 1990 Nancy Leyton was diagnosed as having Alzheimer's disease the couple were compelled to leave their cottage, and returned to Ventnor, where they had first met 70 years earlier.
Paul Henry Leyton, engineer and restaurateur: born Leeds 1 June 1914; Chief Rocket Development Engineer, Saunders Roe 1956-59; Engineering Director, Black & Decker 1959-61; married 1939 Nancy Crinage (died 1993; four sons); died Ventnor, Isle of Wight 4 November 1998.