Beginning his RAF career flying Canberra light bombers in Germany in the 1960s and going on to command one of the last squadrons of Vulcan nuclear bombers in the 1970s, Tim Garden early made himself a reputation as an officer who thought deeply about the capabilities – and limitations – of both tactical and strategic air power in the geopolitical situation confronting the Nato allies in the world of the Cold War and afterwards.

Besides his “frontline” time, which also included command of the large helicopter base RAF Odiham, Garden had a number of important policy appointments in the Ministry of Defence and was Commandant of the Royal College of Defence Studies in the 1990s. It was clear that he would have been a candidate for the very highest positions both in his own service and in the tri-Services defence establishment.

But an academic career attracted him, and in 1996 he retired from the RAF with the rank of air marshal and in the following year went to the Royal Institute of International Affairs (RIIA) as its director. Thereafter his career was as a writer, broadcaster, and lecturer on defence issues in both this country and the US, notably as Visiting Professor in Defence Studies at King’s College London.

Since 2004 he had been Liberal Democrat spokesman on defence in the House of Lords, from which position he had provided a sustained critique of Britain’s and Nato’s performance in the face of the geopolitical problems facing them, both through his statements in the House and the media, and through his foreign and security policy weblog.

Timothy Garden was born in Worcester in 1944 and educated at King’s School, Worcester, from where he went to St Catherine's College, Oxford, to read physics. He joined the RAF as a university cadet and learnt to fly with the University Air Squadron, of which he was a member from 1962 to 1965.

After graduation he began his full-time RAF career and after gaining his wings trained on bombers. His first frontline appointment was in 1967 to No 3 Squadron, operating Canberra strike bombers in RAF Germany from first Geilenkirchen and then RAF Laarbruch.

In addition, Garden was also involved in the “lone ranger” missions often flown by the Canberras along the southern flank of the Soviet Union, flights designed to maintain air crew proficiency in air route procedures for long-distance deployments.

In 1971 Garden returned to England to become a flying instructor and the following year was appointed to command a Jet Provost flying training squadron with which he was to remain until 1975. After passing through the Army Staff College in 1976, he had three years as Personal Staff Officer to the Air Member for Personnel, 1977-79.

The latter year saw a return to oper-ational flying. The delta-winged Vulcan, the most successful of the V-bombers responsible for delivering Britain’s strategic nuclear deterrent in the era before submarine-launched ballistic missiles, was nearing the end of its service career, and Garden was given command of 50 Squadron, one of the last in service. He brought to the appointment his wealth of experience in long-range flying and a care for the efficiency of each of his crews.

By this time it was amply evident that Garden was a man whose natural habitat was the higher echelons of his Service, where politics and professionalism rub shoulders. In 1982 Garden was sent to Cambridge to take an MPhil in international relations before going later in the year to the RAF Staff College Bracknell where he was for the next three years director of defence studies.

But he was back in touch with operations on the front line again in 1985 when he was made station commander at RAF Odiham, Hampshire, the RAF’s largest helicopter base. The fixed-wing trained Garden flew both the Puma and the Chinook helicopters flown from Odiham in a period of intensive operations in Northern Ireland, and this added another dimension to his experience.

By 1987 he was back at the Ministry of Defence in a series of high-level appointments in which the role and equipment needs of Britain’s and Nato’s forces was reassessed as the Soviet Union disintegrated and the Western alliance’s Cold War stance required reexamination. He was Assistant Chief of Air Staff, 1991-92, and Assistant Chief of Defence Staff (Programmes), 1992-94, with responsibility for long-term defence programme planning for all three Services.

Then, in April 1994 he was appointed to the influential – and to him deeply satisfying – post of Commandant of the Royal College of Defence Studies, with the rank of air marshal. There ensued two and a half fulfilling years for him.

Indeed, although a rosy career in the Services beckoned as his tenure of this appointment drew to a close, he was greatly attracted by opportunities of putting his expertise to good use in the world of writing, lecturing and defence analysis, and he decided to retire from the RAF in 1996.

He had been appointed CB in 1992 and KCB in 1994.

After a relatively short period as a website consultant he was offered the directorship of the RIIA at Chatham House. From mid-1998 onwards he was occupied in writing and broadcasting, as well as lecturing, and he also undertook a number of projects for the British and US governments, and for Nato, as well as advice (in 2000, under the auspices of the Adam Smith Institute) to the Palestinian Authority on negotiations with Israel.

In the spring of 2001 he was Distinguished Visiting Fellow and Scholar in Residence at Indiana University, where he returned in 2004 as Wells Professor. He had continued to lecture there regularly by video link. Since 2000 he had been Visiting Professor at the Centre for Defence Studies at King’s College London, where he was particularly involved on the evolution of European defence policies and capabilities. For this he was appointed in 2003 a Chevalier, Légion d’honneur by the French Government.

He had been working as a member for the team developing defence policy for the Liberal Democrats (for whom his wife was to stand for Parliament in 2005), and in 2004 he was created a life peer and made the parliamentary party’s spokesman in the House of Lords on defence.

He brought his long experience of geopolitical realities to his brief, and his regular statements and blogs provided an astute rolling analysis of the problems confronting the Government’s defence policy, over a range of issues, from the future of the UK’s nuclear deterrent to security issues in a world of increased global terrorist activity. He published two books: Can Deterrence Last? (1984), and The Technology Trap: Science and the Military (1989), besides numerous articles and papers.

He is survived by his wife, Susan, whom he married in 1965, and by their two daughters.

Air Marshal Lord Garden, KCB, bomber pilot, academic and Liberal Democrat spokesman on defence, was born on April 23, 1944. He died of cancer on August 9, 2007, aged 63