Nick Nuttall was a man of action, someone who put all he had into accomplishing the task in hand, but he was also capable of taking the longer view. First as a soldier, then as chairman of the family engineering firm, and latterly as a campaigner for marine conservation, he successfully took responsibility for preserving the proud legacy of the past for the benefit of the present generation and those yet to come.

The last of these roles was perhaps the most unexpected and, in its context, the most impressive. In 1979, Nuttall moved to the Bahamas as a tax exile after selling his business. There was little tradition, nor much government encouragement, of expatriates involving themselves in the public affairs of the former colony. However, Nuttall, a keen diver, soon became perturbed by the lack of attention being paid to the visible erosion of the coral reef and the islands’ marine life.

With the backing of Jacques Cousteau, who had a home in the Exumas, Nuttall set up the Bahamas Reef Environment Educational Foundation (Breef). During the next 25 years he transformed almost single-handedly local attitudes to maritime conservation. He spoke to numerous school-children, organised courses for their teachers, and convinced fishermen that changes in their working practices would bring advantages in the long term.

Historically, conservation groups in the islands had bowed to government pressure that itself had been influenced by commercial interests. Nuttall was never afraid to speak candidly to power, nor to agitate for change rather than merely complain, and in time his efforts paid dividends.

Not only did the Government become convinced of the importance of the reef and its species for the future of tourism, but legislation was enacted to reverse the depletion of stocks of the grouper fish, perhaps the Bahamas’ most popular food source. Few others have contributed as much to the islands’ future wellbeing.

Nicholas Keith Lillington Nuttall was born in London in 1933. An only child, he grew up at Lowesby Hall, near Melton Mowbray in Leicestershire, where he developed a passion for hunting. In 1941 his father died of wounds sustained at Dunkirk. Nuttall succeeded in the baronetcy, which had been created in 1922 for his grandfather Edmund, proprietor of the eponymous civil engineering firm, builders of the Mersey Tunnel.

After Eton, where he was an outstanding middle-distance runner, Nuttall was commissioned in 1953 in the Royal Horse Guards. A natural leader, much respected by his men and brother officers for his lack of pomposity, companionable nature and plain speaking, he saw active service in Cyprus during the Eoka crisis and commanded the Guards Independent Parachute Company. He also twice won the Grand Military Cup, the Army’s steeplechase at Sandown.

In 1968, after the death of his mother, Nuttall retired in the rank of major to take over the family firm, which she had notionally run until then. The business was not in the best of health, but Nuttall felt a strong obligation to a company which had enlisted en masse with his father in the Engineers during the war.

Over the next decade he turned its fortunes around, even winning contracts to install underfloor cooling at Mecca, as well as for the prospective (though soon to be cancelled) Channel Tunnel. Then, in the mid1970s, he sold the business to HBG, the Dutch construction group. Thereafter he lived briefly in Europe – for many years he was to winter in Gstaad – before settling near Lyford Cay on New Providence in the Bahamas.

Nuttall was a competitive man, finishing in the top quarter of the field in the New York marathon in his late sixties, but also one of principle. He had generous instincts, and never saw the worst in people or situations, while his charm, disarming sense of humour and love of flirting invariably overcame any resistance to his getting what he wanted.

Latterly he became involved with plans to replant the Caledonian Forest, and while passing Ben Nevis decided to climb it, because he never had. On the way up, he detected that something was amiss, and soon after was found to have lung cancer. He fought it with characteristic bravery, and achieved his ambition to attend the weddings of two of his children this year, including that of his daughter, Amber, to the chef Tom Aikens.

He married first, in 1960 (dissolved 1971), Caroline York, who died earlier this year. They had a son, Harry, who succeeds in the baronetcy, and a daughter, who predeceased them. Nuttall married secondly, in 1971 (dissolved 1975), Julia Beresford and thirdly, in 1975 (dissolved 1983), Miranda Sellers, the former wife of the actor Peter Sellers and now Countess of Stockton. They had three daughters, who survive him, as does his ward, Nicholas Drummond. Fourthly, he married in 1983 Eugenie McWeeney. She and their son also survive him.

Sir Nicholas Nuttall, 3rd Bt, soldier, engineer and marine conservationist, was born on September 21, 1933. He died on July 29, 2007, aged 73