Sir Michael Uren, who has died aged 95, made a fortune in the gritty industrial fields of sea-dredged aggregates and blast-furnace slag recycling – and gave more than £90 million of it to chosen good causes.

Uren was an engineer-entrepreneur whose irrepressible energy and curiosity were directed towards practical achievement rather than profit – but, as he put it, “if those achievements are properly structured in the first place, then money will automatically follow”.

Thus it was that when he sold his Civil & Marine business to the Hanson group in 2006, “a large pile landed on the table, for which Janis [his partner] and I had no need, so we started to use the money for major charitable projects”.

The catalogue of his donations during the last 13 years of his life amounts to a remarkable legacy. The biggest beneficiary was his wartime alma mater Imperial College London, to which he gave £40 million for the foundation of a Bio-Medical Engineering Research Centre which bears his name – bringing engineers, scientists and clinicians together to pioneer medical advances at the college’s western campus in White City.

Uren himself saw the project as “a new Silicon Valley” for innovative biotechnology ventures.

A second strand of his philanthropy favoured ex-services charities and the Gurkha Welfare Trust in Nepal, for which he funded the construction of residential care homes for former soldiers that he liked to compare to the Royal Hospital, Chelsea.

A long personal commitment to charity work for blind children led him to Moorfields Eye Hospital, where he gave more than £3 million for research into treatments for macular degeneration. The private King Edward VII’s Hospital Sister Agnes in Marylebone received more than £15 million to maintain its independence and modernise its facilities.

He also loved animals and was a benefactor of International Animal Rescue for the preservation of orang-utans and other endangered species. Closer to his Kent home, he was a regular benefactor of his local church, St Mary’s Kenardington; his last gift, in June this year, was £1  million to his old school, Sherborne in Dorset.

The “thrilling thing” about philanthropy on such a scale, he recorded, was that it made possible entire projects which could not have happened without his help: “one can’t ask for a bigger reward than that.”

Sir Michael Uren: irrepressible energy and curiosity
Sir Michael Uren: irrepressible energy and curiosity

John Michael Leal Uren was born at Hendon, Middlesex, on September 1 1923, the son of Arthur Uren and his wife Doris, née Leal. Arthur started his working life as a bank clerk in Cornwall and rose to be a director of United Dominions Trust, a City hire-purchase business.

After Sherborne, Michael took a first in engineering at Imperial College London in three years rather than the normal four, while also serving in the Home Guard. In 1943 he was conscripted into the RNVR and commissioned as an air engineer officer in the Fleet Air Arm – passing out top of his intake and serving in experimental and development squadrons until he was demobbed in 1946.

He then joined the civil engineering firm of Sir Alexander Gibb & Partners and spent five years based in Tehran, developing hydro power and water supply projects in Iran, Iraq, Syria and Jordan.

Returning to Britain, he moved to the Cementation Company to work on the 12-mile Bowland Forest tunnel carrying Lake District water to Manchester, and later on a hydro scheme on Loch Tay. He changed firms again to work in New Zealand, building a dam on the Clutha river to provide power for the South Island.

Back in England in 1955, Uren partnered with John Hobbins, with whom he had worked in Iran, in a venture shipping sand and gravel in and out of North Sea ports with a seagoing barge that had been built for the Gallipoli landings.

While Hobbins and his wife took the vessel to sea as master and mate, Uren took another job “to earn money to pay the wages on Friday” as a director of Dowsett Engineering, which worked on the construction of the M1 motorway.

The success of the barge business allowed Uren to leave Dowsett in 1964, when he and Hobbins designed and built a self-loading dredger to suck sand and gravel from the North Sea bed and discharge it at a concrete works in the Thames Estuary.

Their fleet expanded to five dredgers servicing numerous concrete plants on both coasts of the North Sea – and, to Uren’s satisfaction, saving some 600 acres of agricultural land per year from being dug up for the extraction of onshore aggregates.

Meanwhile, in their own research laboratory they discovered that high-quality cement could be manufactured from blast-furnace slag (a by-product of the steel industry) using only one-fifth of the energy required to make conventional Portland cement – and with much lower carbon emissions.

A first factory was opened at Purfleet in 1981; others followed adjacent to steelworks at Llanwern, Scunthorpe, Port Talbot and Redcar and later in Slovakia and Florida. It was a lucrative business model, since they were paid once by the steel industry to take the waste material away and again by the construction industry for the cement they produced.

Uren first sold a majority interest in Civil & Marine in 1990 but remained involved and bought back most of the group in a management buy-out two years later. He was 83 when Hanson paid £245 million for the business in 2006 – and the proceeds made little difference to his lifestyle. He continued to live in a modest Kent farmhouse and did not even buy a new car, though he did relocate and restore a fine medieval barn.

Uren was a long-serving trustee, chairman and benefactor of the Royal London Society for the Blind (now the Royal Society for Blind Children) and was instrumental in the development of new education facilities, and a working farm, at its Dorton House estate in Sevenoaks. He was also a past Master of the Cordwainers Company.

He was appointed OBE for his work for the blind in 1999 and was knighted in 2016. Well into his nineties, he was still vigorously engaged with the causes he supported and exploring new projects of his own – including the idea (thwarted by the wrong kind of soil) of turning his farmland into a vineyard.

He married, in 1955, Serena Anne (“Jane”) Peal; they separated in 1996 but remained good friends. He is survived by his partner of later years, Janis Bennett, and by Jane and their two sons.

Sir Michael Uren, born September 1 1923, died August 9 2019

From The Daily Telegraph, 17 September 2019.