Lady Mairi Bury: Chatelaine of Mount Stewart who met Hitler and Von Ribbentrop

The cast of characters in the life of Lady Mairi Bury, member of a remarkable aristocratic family, included both Winston Churchill and Adolf Hitler, as well as a host of major figures in politics and high society. Churchill was most unimpressed when her father, a former British air minister, flew to Berlin to talk to Hitler. The teenaged Mairi herself, who went along with him, was less than impressed with the German dictator.

"I thought, what a nondescript person," she recalled in later life. "You would never have picked him out in a crowd. No, I'm afraid no aura of evil, no sense of foreboding, a rather quiet voice. In fact, little stands out other than the memory of his most extraordinary blue eyes."

Her father, Lord Londonderry, spent years in vain attempts to reason with Hitler and other Nazis. At one point he brought to Mount Stewart, his grand home near Belfast, senior Hitler official Von Ribbentrop, who arrived "with a noisy gang of SS men."

Londonderry, who was described as "clueless, condescending and impossibly rich," was so naive that he spoke of Hitler as "very agreeable, a kindly man with a receding chin and an impressive face." Londonderry, himself described as "almost theatrically eighteenth century," placed his faith in the type of old world personal contact practised by Lord Castlereagh, his foreign-secretary ancestor.

While Londonderry was not a Nazi sympathiser, his futile crusade meant that he has ever afterwards been classified as an appeaser, a label which most have regarded as a badge of something close to shame. Taunted as "the Londonderry Herr," he himself was to admit: "The war, the crisis of our lives, finds me completely isolated and under a sort of shadow which I cannot get away from." As the Battle of Britain was fought he mourned: "I backed the wrong horse."

He demonstrated lack of insight on a heroic scale when he could not understand why Churchill – his cousin – would not put him in the Cabinet. He wrote in bafflement: "Winston's determined attitude towards me is incomprehensible, and I doubt if I shall ever know why he went out of his way to destroy me." Churchill scathingly called him "that half-wit Charlie Londonderry."

Lady Mairi viewed the whole sorry episode in personal terms, later stoutly defending her father. "He lived through one hideous war and wanted to do everything possible to prevent another," she maintained. "Obviously those who criticised him had absolutely no idea he was working for peace, and that for the sake of it my father would have gone anywhere, seen anyone. I find his motives deeply worthy. One's deeply proud of those efforts. How could you not be?"

She was no more a Nazi sympathiser than her father, yet curiously for decades she kept, and indeed put on show, a prominent relic of the episode. At Mount Stewart, the magnificent County Down mansion where she spent her life, she had on her mantelpiece a striking 18in high statuette of a helmeted Nazi stormtrooper proudly holding a flag.

Its exhibition seems to have been an outstanding example of aristocratic nonchalance on her part. The porcelain figure was in effect on public display, since decades ago the house and its glorious gardens became a National Trust property, with Lady Mairi continuing to live in one part of it. This meant that thousands of visitors filed past it every year. One of these, who noticed it with great surprise, was the distinguished Hitler historian Sir Ian Kershaw. Intrigued, he investigated its origins, and the result was his 2004 book, Making Friends with Hitler: Lord Londonderry and Britain's Road to War.

It turned out that it had been given to Londonderry by Von Ribbentrop during his visit. As a girl, Lady Mairi cared even less for Von Ribbentrop than for Hitler, remembering him as "the most arrogant creature". (Germany's foreign minister throughout the war, he was hanged after the Nuremberg trials.)

Lady Mairi was born as Mairi Vane Tempest Stewart into a family of fabulous wealth and famous social connections. Mount Stewart's comfortable grandeur was impressive in itself, but the family had a far larger house in the North-east of England. There they possessed vast tracts of land and an immense coal-mining empire. They also owned Londonderry House in London's Park Lane, where 44 servants toiled within an imposing structure – which was damaged in the War by German bombers.

Lady Mairi's mother Edith was the most celebrated society and political hostess of her day, throwing parties with up to 2,500 guests. They included royalty and prime ministers such as Stanley Baldwin, as well as a glittering array of artists and literary figures. She was thus brought up in a life of privilege and luxury, privately educated, travelling all over the world and presented as a debutante to royalty. It was said of her in later life that "her accent remains quintessentially that of the Queen Mother".

Of the social life at Mount Stewart she reminisced: "One rather took it all for granted. In those days there were huge house parties – compared with now, the place was crowded with people. There were three footmen, a groom of chambers, butler, and numerous housemaids and kitchen maids."

Presiding over all of these stately homes was Lady Mairi's mother Edith, who was both a natural society hostess and a woman who put much effort into advancing her husband's political career. Of all the political relationships she struck up, the best-known was that with Ramsay MacDonald, the first Labour prime minister. Widowed and lonely, he became infatuated with Edith, staying at Mount Stewart and writing many gushing letters to "my dearest friend of all," signing himself "your attendant ghillie".

His closeness to her caused unease in the Labour Party, especially when he gave her husband a cabinet post. MacDonald told Edith he had overheard one Labour MP saying of him in the Commons lobby, "A few months ago he sang 'The Red Flag', but now he whistles 'The Londonderry Air'."

Stanley Baldwin wrote to a family member saying bluntly that 90 per cent of people regarded her friendship with MacDonald as "an act of political expediency" to help Londonderry's career. The worries of many on the left that MacDonald was being corrupted by a hostess who was both high society and High Tory were confirmed when he struck up an association with the Conservatives and formed a National Government, which led to his expulsion from the Labour Party.

Most think that Edith and Ramsay did not actually become lovers, although the fact that she had a tattoo of a snake on her left leg, beginning at her ankle and wending its way intriguingly upwards, caused many to assume she was "a fast woman". In fact it was her husband who was a serial adulterer, a trait which hurt Edith deeply. She coped with it by utilising her skills as a hostess and having several of his mistresses to her home. Some of them, including one called Olive, were put to some use: "Olive came round and I got her to take Mairi to the circus," she wrote.

Mairi was married in 1940, to Derek William Charles Keppel, Viscount Bury, and had two children, before their divorce in 1958. In the Second World War she served in the Women's Legion, an organisation founded by her mother in the previous war. She recalled: "I worked down at the docks in London driving pick-ups. I wouldn't have gone to fight or anything like that, but I was all for women's rights".

For decades a staunch Ulster Unionist, she switched in later years to supporting the Rev Ian Paisley, describing the Good Friday Agreement, on which much of the current peace process is based, as "infamous".

David McKittrick

Mairi Elizabeth Vane Tempest Stewart: born Mount Stewart, Co Down 25 March 1921; married 1940 Viscount Bury (two daughters, divorced 1958); died Mount Stewart 16 November 2009.