Major Derek Cooper is one of the last of that endangered species, the English gentleman. Though his own memoirs, Dangerous Liaison (published last year by Michael Russell), were subtitled "an Irish Pimpernel's war diary", Cooper was born in Kent, in 1912, into what his sister called the "wealthy middle class" of England. The Coopers owned a printing firm and his mother's family, the Tillings, had a bus company. The Coopers were more "upper" middle than the Tillings; but the Tillings, whose company was nationalised in 1947 for [pounds]27 million, had more money.

Derek Cooper's father served in the first world war in India, where a mutinous "Mohammedan" soldier killed him. Derek had just turned three. One of his earliest memories is of German Zeppelin raids, when he sat on the knee of the family's parlour-maid-turned-nanny, Alice, "sucking Horlick's tablets while she sang wartime songs like 'Goodbye Dolly', 'Keep the Home Fires Burning', and 'Tipperary'." Derek's mother married an army friend of her late husband's and moved with him to India, leaving Derek and his two sisters behind. She returned two years later to a grand but spartan Northern Irish house, whose ghosts forced the children to take their bull terrier along the dark corridor to the only lavatory.

In 1930, aged 18, Derek became an apprentice engineer for the Tilbury Contracting and Dredging Company. He enjoyed working and socialising with the labourers as he had with farm workers in Ireland. In 1932 the company sent him to Palestine, where it had the contract to enlarge Haifa harbour. Thus began a lifelong attachment to Palestine, to which he would return over the next 60 years as soldier, aid worker and human rights activist. In 1933 he became a special constable during the riots by Arabs, who were angered at the increase in Jewish immigration - from 2,178 in 1926 to 30,327 in 1933. The Arabs feared that the Zionists among the arriving Jews intended to displace them, which they did 15 years later. Derek received a helmet and baton that he was not, to his relief, required to use.

With Haifa port completed in 1934 and his stepfather having died, he returned to help his mother manage the farm. At his sister's wedding he met Pamela Armstrong-Lushington-Tulloch. They married in 1937. By then he had become a reserve officer in the Irish Guards. He went on to have a good war, first siting defences for the Brown Line to protect London from German invasion. He survived bombing raids to pull airmen from burning Spitfires and civilian casualties from rubble, a feat he was still performing in 1982 in his mid-seventies during the Israeli invasion of Lebanon. In 1942 he transferred to the Second Household Cavalry Regiment, an armoured reconnaissance unit, and landed at Normandy in 1944. The Times wrote last year that Derek "single-handedly liberated a Belgian town, gathered crucial intelligence on key battles and survived ambushes and accidents...He also drank more bottles of champagne than he can remember." Derek's diary, quoted here, gives vivid accounts of the engagements in France, the costly attack at Arnhem Bridge and the Battle of the Bulge.

Nothing was as certain as it seems in hindsight. "The people in my house," Derek wrote of a Belgian family, "are very nervous and afraid the Germans are coming back; they may well be right, many villages have been taken with reprisals and burning." By 1945 he was in Germany and had won the Military Cross. The Life Guards were posted to Palestine in 1946. Derek was in Jaffa when the Zionist forces attacked in April 1948. "Most of the civilian population had by now left," he wrote, "but, to make sure, loudspeakers from the Jewish side announced, 'Get out with the British, remember Deir Yassin'." Deir Yassin was the unarmed Arab village attacked by Menachem Begin's Irgun forces on 9 April. In his memoirs, Begin credited the massacre of its inhabitants with frightening thousands of Arabs out of the country. The British policy of securing only the roads needed for the British evacuation on 15 May left the way to Deir Yassin blocked when Derek attempted to relieve it. This later determined him to make up for his country's betrayal of the Palestinian Arabs, most of whom became refugees.

When the Life Guards returned to England, Derek's marriage was ending. Of Derek's wife, who had been without him for nearly ten years, Baynes writes, in terms only a discreet gentleman would use, that "her affections had been switched to Tom Fairhurst, whom she eventually married". Then Derek met another Pamela, the young widow of an officer killed in north Africa. Pam Ruthven had two sons, Greystell and Malise, and lived at Windsor Castle, where her father-in-law, the Earl of Gowrie, was deputy governor of the Norman Tower. Derek's divorce and Pam's involvement with him attracted the interference of the king's "Uncle Algie", the Earl of Athlone, and his wife, Princess Alice. Athlone was colonel in Derek's regiment and the castle's governor. To preserve a propriety the royal family would not recognise today, Derek resigned his commission and Pam left Windsor. They married and moved to Ireland.

For many retired officers that would have begun a quiet life on the farm, perhaps writing memoirs and raising horses. Derek and Pam Cooper spent most of the next 40 years aiding refugees in the field. They delivered medical aid, first to those escaping Hungary in 1956, and then in Palestine, under live fire as well as political attack. Although the western world abandoned the Hungarians and the Palestinians, the Coopers did not.

Now in their late 80s, they fight on. It is sad only that Derek Cooper, the quintessential English gent, should have lived into an age when peerages and knighthoods go to every spiv who ever oiled up to the Thatcher-Blair money machines, while eluding those who have served their country and its post-imperial victims.