If you had been ­rummaging in Brighton’s antiques district in the late 1960s, you would have spotted a shop with the owner’s aristocratic-sounding name proudly over the door: ‘Edith Tudor Hart’.

Inside was an exquisite ­selection of Wedgwood brooches and silver cutlery. Mrs Tudor Hart, an ­elegant lady with an exotic ­European accent, clearly had great taste.

What her customers did not know was that she was also a Russian secret agent who had recruited Kim Philby, aka ‘The Third Man’, to spy for Russia before the war.

Turned her hand to antiquities 

Decades later Anthony Blunt, another member of the Cambridge Five espionage ring, confessed to his MI5 interrogators that Edith Tudor Hart was ‘the grandmother of us all’.

Edith’s life is not easy to untangle for the simple reason that she took care to leave few traces. (Her code name, though, remained ‘Edith’ which you can’t help feeling was a bit of a giveaway.)

Born into a cultured Left-leaning Jewish family in pre-war Austria, she fled to Britain in 1933 once ­Hitler’s evil ambitions had become clear. A short-lived marriage to a doctor whom she met through the Communist party gave her a British passport and a haven from the European concentration camps in which many of her extended family were murdered.

Daria Santini is quite clear that Edith’s motivation was never financial – she received no payment for her recruitment work for the NKVD, the forerunner of the KGB.

But like so many idealists of her generation, she was convinced that Communism represented the best and fairest political ­system, not to mention functioned as an essential bulwark against fascism.

A Woman Named Edith is available now

Edith’s particular concern was child poverty (she had trained as a Montessori teacher) and it struck her as obscene that, in a country as ‘civilised’ as Britain, millions still went hungry.

In parallel to her espionage activities, Edith Tudor Hart was a professional photographer, having trained at the world-­famous Bauhaus school. She specialised in working-class life in a way that never felt patronising or posed.

One of her most striking ­pictures shows a ragged little girl staring with disbelief at a baker’s window stuffed full of cakes and pastries that she could never afford. Some of Edith’s best work was featured on the cover of ­Picture Post, one of Britain’s most prestigious magazines.

Stylish and vivacious, Edith Tudor Hart used her charm to recruit people, men particularly, to work as Russian secret agents.

She had talent-spotted Kim Philby, a Cambridge graduate, and introduced him to the NKVD’s spy master, Arnold Deutsch. It wasn’t, however, until after the Second World War when Guy Burgess and Donald Maclean – other members of the spy ring – fled to Moscow that the British authorities redoubled their efforts to pin Edith down as a Russian asset.

MI5 bugged her home, opened her post and, one day in 1952, barged into her flat and questioned her for several hours.

She claimed to have resigned from the Communist party years ago and looked blank when they mentioned the name Kim Philby.

The revelation of Joseph ­Stalin’s cruelty to his own people – this was the age of the Gulag – led to feelings of intense disenchantment with the Soviet system.

In the end a nervous breakdown meant Edith tucking herself away in Brighton’s cobbled lanes with her photographic negatives, antiques and memories of a secret life she could share with no one.