His PhD thesis focused in part on Lord Castlereagh, one of the Irish architects of the Act of Union — the man of whom Shelley wrote: “I met Murder on the way/He had a mask like Castlereagh”, an eerie foreshadowing of how Kissinger himself would be viewed.

For most, he will be forever linked with Richard Nixon, however. Kissinger was the key man in Nixon’s presidency: in negotiations with Vietnam he often deployed what he himself termed the madman theory: “I want the North Vietnamese to believe I’ve reached the point where I might do anything to end the war.”

His advocates can still point to considerable achievements in that period as US secretary of state, from 1969 to 1976.

Kissinger was the chief negotiator at the Paris talks in 1973 where the US eventually agreed to to leave Vietnam after years of conflict. He helped to open up relations between China and the US, a development which led to Nixon’s
historic visit to that country and heralded a seismic change in attitudes.

In 1974, he negotiated an Israeli troop withdrawal from Sinai which paved the way for an end to the oil crisis — again, a hugely significant development at a time when soaring fuel prices were paralysing many countries.

Yet there was a far darker side to Kissinger’s long career — which led to him being labelled a war criminal. His influence in Africa is blamed for extending the lifespan of the apartheid regime in South Africa due to US involvement in the civil war in Angola (which is one of the most heavily-mined countries in the world to this day). In 1969, he came up with the plan to secretly bomb Cambodia, a neutral neighbour of Vietnam.

Kissinger backed Indonesia’s invasion of newly independent East Timor in 1975. When Chile’s democratically-elected president Salvador Allende was overthrown by the Chilean army in 1973, Kissinger told Nixon: “We helped them.”

These decisions cost hundreds of thousands of lives. Little wonder humorist Tom Lehrer said: “Political satire became obsolete when Henry Kissinger was awarded the Nobel Peace Prize” (in 1973).

Kissinger had the ear of 12 successive US presidents and was frequently consulted by media outlets, settling into a lengthy retirement as the éminence grise of international
diplomacy — but the shadow of his misdeeds was never
forgotten.

His version of diplomacy was different to most practitioners’ because Kissinger invariably had the big battalions on his side and negotiated from a position of strength. His decisions left a trail of misery and death across continents and generations — some view his bombing of Cambodia as paving the way for the Khmer Rouge regime, for instance.

The legacy stains what was also an extraordinary rise to prominence from unpromising beginnings. Kissinger’s family escaped Nazi Germany, arriving in New York in 1938.

Many years later one of his brothers was asked why he had a normal American accent while Henry had famously retained the heavy German accent he had picked up in their native country.

“You change your accent by listening to other people,” said his brother. “Henry never listened to anyone.”