My father, Jack Leonard, who has died aged 87, was an innovative and highly respected engineer and businessman. Under his leadership the company he co-founded, Eurotherm International, became a world leader in the supply of temperature control devices to chemical, glass, cable and aerospace manufacturers.
Jack was born in Prestwich, Manchester, the son of Leonard Lazarus (who later changed his surname to Leonard by deed poll), a film distribution manager for Warner Brothers, and Cecilia (nee Phillips), a housewife. He was educated at Manchester grammar school before serving an engineering apprenticeship at Ferranti and going on to gain a BSc in electrical engineering in 1953 from Manchester University, where he earned his PhD in control systems in 1957.
He joined Bruce Peebles & Co engineers in Edinburgh and, in 1961, developed a foetal monitor that allowed detection of heartbeats as early as 20 weeks – a significant development at the time and one that allowed potential problems to be picked up earlier.
After moving to an American company as director of marketing, Jack became frustrated at the lack of product development, and in 1965 joined forces with three colleagues to raise £17,000 and form Eurotherm in Worthing, West Sussex.
Five years later, turnover had reached £1m and global expansion was under way. In 1970 Jack moved his young family to Virginia in the US to establish Eurotherm Corporation, and by 1977 he was group managing director. The company was floated on the London Stock Exchange in 1978 to an enthusiastic response. He retired as chair in 1996, with Eurotherm valued at £500m and employing more than 2,000 people. Eventually the company was taken over by Schneider Electric.
Outside work Jack liked to fly helicopters, but he also turned that interest into a business opportunity, setting up Fast Helicopters at Shoreham airport, West Sussex, to provide flying lessons and tours.
Jack met his first wife, Audrey (nee Lamb), at Manchester University, and they married in 1958, raising four children in their homes in Sussex and Virginia. She died in 1998.
He is survived by his second wife, Margaret (formerly Smith), his children from his first marriage, Jonathan, Andrew, Megan and me, and five grandsons.
