Rupert Harding-Newman was almost certainly the last survivor of the band of enthusiasts for the Western Desert of Egypt, whose excursions there during the 1930s were to become the inspiration for the Long Range Desert Group. He accompanied Major (later Brigadier) Ralph Bagnold on a desert expedition to the Tibesti area of northern Chad in 1932, so he was an obvious candidate for the reconnaissance and raiding force that Bagnold persuaded General Sir Archibald Wavell to form in 1940.

Before then, Harding-Newman had taken part in another expedition in the Western Desert covering more than 6,000 miles of mainly unexplored terrain during three months in early 1935. This experience of negotiating soft sand, operating without resupply of water and, above all, in desert navigation was to prove invaluable to the LRDG. But when Bagnold asked for him, Harding-Newnam was serving with the British Training Mission to the Egyptian Army, a post he was not permitted to leave.

In one regard this was to serve Bagnold's interest. He had invented a simple sun-compass specifically for desert navigation, but the Army had rejected it in favour of the complicated Coles sun-compass. Fortunately, the Egyptian Army had bought Bagnold's version and Harding-Newman was able to buy some back. He also succeeded in persuading the Egyptians to provide a consignment of Chevrolet 30cwt trucks, which were infinitely more suitable for desert use than anything the British Army had to hand.

Although Wavell had been convinced of the potential usefulness of the LRDG as a source of intelligence on Africa Corps movements and reactions to the Eighth Army's own deployments, the Eighth Army staff were sceptical initially. By the autumn of 1941, Harding-Newman had secured release from his job with the Egyptians and joined Headquarters Eighth Army. There he became the conveyer of orders to the LRDG, a line of communication which was further enhanced when the LRDG's operating base was moved north from Kufra, beyond the Great Sand Sea, to Siwa close to the main battle area.

Despite achieving so much on the unit's behalf, Harding-Newman was never able to join the LRDG. In early 1942, he was Brigade Major of the 22nd Armoured brigade during fierce fighting near Hagrag el Raml and was recommended for the DSO, but instead received the Military Cross.

On the eve of the battle of Alamein he was flown to London in response to an urgent War Office call for an officer with knowledge of fighting in the desert. For the next two years he worked in the War Office specialising in tank design and development, a subject in which he had been involved in the 1930s.

By the time his London assignment was completed the war in the desert was over. He was chief instructor at the wartime Sandhurst until appointed to command a training regiment of the Royal Armoured Corps in August 1944. In consequence, he was not able to see active service again but, in 1946, he went to Greece as a senior staff officer with the British Military Mission advising the Greek National Army during the civil war against the Greek communist forces of ELAS.

Rupert Norton Harding-Newman was born in 1907 in Cambridgeshire, where his father was the estate agent for Chippenham Park. He was educated at St Edward's School, Oxford, and RMC Sandhurst, from where he was commissioned into the Royal Tank Corps (later the Royal Tank Regiment) in 1928. He served with 6th Battalion in Egypt until 1933 when he returned to England. Interest in the desert and development of armoured warfare there led him to take the opportunity to return to Egypt with the 1st (Light) Battalion RTC in 1935.

It was during this period of his service that he became involved in the trials of the Mark VI Light Tank, which entailed testing the vehicle over 1,000 miles of desert. This work brought him to the attention of the Master-General of the Ordnance who wrote to congratulate him on the detailed nature of the trial report.

After the war, he commanded 8th Royal Tank Regiment in Germany, 1950-52, and served in a number of instructional and technical appointments as a colonel before being promoted brigadier to command the Royal Armoured Corps Centre at Bovington in 1958. He was also an ADC to the Queen from 1959 to 1961, when he retired from the Army.

In recognition of his exploration work in the Western Desert before the war, he was appointed a Fellow of the Royal Geographical Society in 1935. After retirement. he moved to Scotland in 1996 and became a member of the National Trust for Scotland. He was also a member of the Wildlife and Wetlands Trust and of the Countryside Alliance.

He married Muriel, eldest daughter of Colonel J.D. Searle in Cairo in 1939. She died in 2002. He is survived by their son and twin daughters.

Brigadier R. N. Harding-Newman, MC, traveller in the Western Desert and Commander of the RAC Centre, 1958-61, was born on December 5, 1907. He died on October 22, 2007. aged 99