John Julius Norwich, chairman of the World Monuments Fund in Britain and, for 30 years, Chairman of the Venice in Peril Fund discovered a love of architecture while a junior diplomat in Cold War Belgrade. It was then, in the mid 1950s, ‘rather bleak with nothing in the shops. The embassy didn’t have a house and we were living in a grim hotel, so I think by way of compensation, I was sent off on tours of the country and began to discover the architecture of the Greek and Byzantine worlds. I was also inspired by a cruise round the Aegean with friends, including Paddy Leigh Fermor’.

He moved on to work in the embassy in Beirut, which consolidated his interest in the Mediterranean: ‘It was a complete contrast to Belgrade we lived in a lovely house in the Venetian style, with views of the mountains and the sea.’ In 1958, Beirut erupted into civil war and he was shot in the head ‘the shot turned out to have been fired by a policeman’.

He returned to London to work on the Middle Eastern and Disarmament desks, but left the Foreign Office in 1964 to devote himself to writing. ‘I never regretted it for a second. I had visited Sicily and was amazed at the meeting of three great civilisations (Latin, Greek and Arab), but came home and found no readable books in English on Sicily at all, so I decided to write one.’ It turned into a two-volume history. Some 45 years on, and he still writes most weekdays in the London Library. Now working on a history of the Papacy, he recently edited the diaries of his MP father, Duff Cooper (later 1st Viscount Norwich), who resigned as First Lord of the Admiralty in protest at the Munich agreement.

‘I can remember his resignation well. He received millions of letters of support, and the house was suddenly full of secretaries making sure every one was answered; I was about 10 and faked his signature on quite a few replies.’ John Julius’ mother was the incomparable society grande dame, Lady Diana Cooper: ‘She was extremely beautiful and liked to make things hum. She used to say “I have always had publicity”. She was a celebrity as well as the glamorous daughter of a duke (although we now know he wasn’t her father), but unlike so many modern celebrities, she really was huge fun.

‘She was a wonderful mother and taught me to read from a book called Reading Without Tears, published in 1860, based on gruesome stories of people being poisoned or drowned.’ Lady Diana had a lively group of artistic friends, such as Rex Whistler, Cecil Beaton, and Duff’s friends were more serious men of letters such as Maurice Baring. In 1944, Duff became the first UK ambassador to liberated Paris.

‘My father expected to be kicked out of the embassy after the 1945 Labour victory, but Ernie Bevin had to come and spend time in Paris, stayed in the embassy, and rather fell in love with my mother, so we stayed a bit longer. Bevin didn’t like talking business after dinner, and preferred, much to my father’s irritation, to sing music-hall songs with my mother, with me at the piano.’

In 1970, John Julius became Chairman of the Venice in Peril Fund (in 2000, he handed over to Anna Somers Cocks), using his legendary charm and enthusiasm to garner support for the preservation of that great city. He recalls with particular affection his first visit with his father when he was a teenager. ‘He said we’d only go into two buildings, St Mark’s at the beginning, and Harry’s Bar at the end, and in between we would just walk.’The greater frequency of flooding remains a concern, as is the decline in Venice’s indigenous population, now down to about 55,000. I believe it was about 155,000 in 1970.’

The World Monuments Fund in Britain also extends to pro-jects in Russia. ‘Our finest British campaign has been the restoration of St George’s Bloomsbury. Everyone should go and see it. Our annual watch list of endangered monuments achieves a lot by turning the spotlight on great buildings at threat, and getting them into the wider consciousness. As Morris said, once lost they can never be replaced.’