Ida and Louise Cook appeared to outsiders as two ordinary sisters from the suburbs. They travelled into London every day, working hard at their lowly jobs for the civil service and coming home to warm and supportive parents. They never expected to marry. They were part of the “singled out” generation that suffered because hundreds of thousands of young men had been killed in or traumatised by World War One. But, inside the Woolworth cardigans, tweed suits and sensible shoes, were two passionate hearts and courageous spirits. They lived for opera, and the singers who breathed life into the words. Neither sister ever played an instrument nor even had music lessons, yet opera became the essence of their adult lives. It was not only what transformed the humdrum into the spectacular it was what led them into dangerous work as undercover rescuers, the least likely of scarlet pimpernels.

Now, if that sounds like the introduction to a Mills and Boon romantic novel perhaps that’s not all that surprising. Ida was one of Mills and Boon’s most successful – and initially daring – authors. Her first book for them, published in 1935 while she was still working as a civil service typist, was an extraordinary story called Wife to Christopher, a page turner with a violent marital rape at the heart of the story. She wrote of bigamous marriages, adulterous affairs and illegitimate babies dying at birth and insisted it all came from her highly active and vivid imagination.  It was the financial success from the novels which gave the Cook sisters enough income to start visiting opera houses around the world and it was the world of opera which in turn led the sisters into a life more exciting and spectacular than many an opera plot. In Ida’s imagination, anything was possible and lives could be transformed.

It all started when Louise, in her lunch hour, wandered into a lecture about music in the Board of Education and this persuaded her to spend a recent bonus on the deposit for a £23 wind up gramophone – a vast sum. But it came with ten classical records free – Bach and Gluck and some melodies from Puccini including un bel di, vedremo sung by Amelita Galli Curci. They were immediately captivated. As soon as they could, they went to hear Galli Curci at a concert performance at the Albert Hall, but as she performed full scale operas only in New York they had no idea when they would hear her again. So they wrote a fan letter, telling the great diva of their plans to save enough money within five years to go and hear her sing in New York. Amazingly, she replied: “if you ever succeed in coming to America you shall have tickets for everything I sing.”

They scrimped and saved often eating nothing but brown rolls for lunch and Ida now tried her hand at writing. In the civil service magazine, Red Tape, she recounted: “Fortunately we have always realised the futility of grumbling enviously about someone else’s salary. It only makes you overlook what you can do with your own.”

And they sewed. They had bought patterns from Mab’s Fashions, a magazine intended for the new breed of female typists, and made their own outfits which they were intensely excited about. They both had fur-collared opera cloaks and glittery knee length dresses – pink and silver for Ida, scarlet for Louise. They sailed the Atlantic on SS Berengaria, 3rd class, in December 1926 and went to the Met for the first time to hear Galli Curci sing la Traviata. It was the most extraordinary experience for these two young women and especially when Galli Curci picked them out in the audience and waved. This, they told their parents in letters home, was “a truly romantic gesture.” From now on they were hooked. The only question was how to pay for their growing addiction. Ever since the 1926 trip, when they had relied on Mab’s Fashions, Ida was writing occasional pieces for the magazine about anything she could think of. But she did not take herself seriously as a writer. It was merely a means to an end. Music was what they lived for and it was already transforming their lives. The transformative power of music was clear to them very early on. It enabled them to dream.

Then, in 1932, Mab’s editor, Miss Taft, offered Ida a job as a sub-editor. She refused because working as a Civil Servant was hugely prestigious and there was a pension. But in 1935 they had spent every penny they earned. So Miss Taft suggested that Ida try her hand at writing a serial; something strong, she said. Wife to Christopher was the result and Miss Taft was at first rather shocked by the sexual frankness.  But she then introduced her new star writer to a young publisher called Charles Boon. Over the next 50 years Ida was to write 129 novels for Mills and Boon most of them in her study at Morella Road, South London. By the 1930’s Ida was earning £1,000 a year from her books, four or five times what she might have expected as a typist. She took the name Mary Burchell and she was never short of an idea for a novel. She was by nature a tale spinner she explained later, who believed in the power of romance and was passionately interested in people. Mostly her women were capable heroines able to cope with whatever life threw at them.

But the writing was always a means to an end, the end being the music and especially the stars who performed it. They were by now good friends with Lita Galli Curci and her husband Homer.  Lita called them ‘My English girls’ and invited them to stay at their home in the Catskills. And they had joined the regulars who queued up outside the Royal Opera House Covent Garden for the cheap gallery seats. They enjoyed the cameraderie of the queuing system, hiring the collapsible stools for a few pence and then waiting outside the stage door, hoping for an autograph or better still a snap of one of the stars as they arrived, took a break or left. They had bought a ten shilling box brownie camera for the purpose. In 1934, completely unaware of the menacing situation in Europe, they were queuing up on their stools as usual for the first performance in London of the new Strauss opera, Arabella. In the list of artists they noticed some who had never been to London before including Clemens Krauss, the charismatic and controversial Austrian conductor known to set audiences alight with fervour. Krauss, an elegant, sometimes dictatorial conductor, was by virtue of his friendship with Richard Strauss, a direct link to the source of musical creation. Strauss himself had given the company directions the previous year in Dresden. He and his glamorous wife, the Romanian soprano Viorica Ursuleac, had what today would be called A-list celebrity status. One lunchtime, as the Cooks waited patiently by the stage door, they noticed a very impressive and handsome man emerge. “That’s Clemens Krauss,” everyone started whispering.

“Privately I thought he looked almost too good to be true,” Ida wrote later of that moment. He was so completely the great stage figure that I felt cynically sure he would turn out to be merely someone’s husband or a chance friend of one of the singers.”  But she asked to take his picture, prepared for the sort of rebuff he was famous for, and was surprised when he reflected a moment and obliged. After the snap, Clemens Krauss kissed their hands. Ida and Louise thought that was wonderful. The next day Ida returned to ask Ursuleac to sign the picture. Herr Direktor had left the country, she explained, but urged the women to come to the Salzburg Festival where Krauss was a regular conductor from 1926 to 34 so that he could sign it too.

The sisters could not resist their summer trip to Salzburg that year especially now that they had been urged by Ursuleac to come. But 1934 was the year Dollfuss, the Austrian Chancellor, was assassinated in a bungled Nazi coup attempt – as the sisters learnt on the train going to Salzburg.
“I blush now to think how ignorant we were of the significance of this event … we were concerned with only one aspect of the murder: would it put a stop to our holiday?” Ida wrote later. But in fact no music lover that summer could have avoided the sense of menace, the atmosphere of doomed enchantment that hung over the festival. And right in the centre of this maelstrom was Clemens Krauss, the man they were hoping to meet again for his signature.

The sisters pursued Ursuleac more than Krauss on this trip sending her bouquets of red roses. It was safer that way and sure enough she became smitten by the sisters. They were charming, they were fans and they were deeply knowledgeable about the art of performing opera. She was genuinely captivated by the pair who now attended dress rehearsals as well as the real thing. Ida wrote home to her parents: “She thinks we’re darlings.”  She did not tell her parents what the hugely charismatic Krauss thought of the two women he now called the Cooksmaedschen.

Ida and Louise probably knew nothing of Krauss’ background nor of how, in 1933, he took over the preparations for the premiere of Strauss’ Arabella when the conductor Fritz Busch (a non-Jewish anti-Nazi) resigned in protest. Two years later he gave up his Vienna positions, becoming director of the Berlin State Opera after Erich Kleiber, another non Jew but anti Nazi, resigned in protest over Nazi rule. In this case the issue was the Nazi attitude to Alban Berg’s second opera, Lulu.  Krauss’ own position on Nazism was unclear although he enjoyed a close relationship with Nazi official Alfred Frauenfeld and it has been claimed that he sought Nazi Party membership in 1933. In 1937 he was appointed Intendant of the Munich National Theatre following the resignation there of Hans Knappertsbusch. Later – after the Munich Opera House was bombed, shutting it down – Krauss returned to conduct the Vienna Philharmonic until it closed shortly before the end of the War.

In 1935 when Ursuleac said goodbye to the sisters in Amsterdam, she tossed them an aside…would they please look after a very dear friend, Frau Meyer-Lissman, the official Salzburg lecturer who went to all the top hotels and gave talks on the operas, when she came to London? They promised they would without understanding why she needed their help. They did not know any Jews until then nor did they understand what it meant to be Jewish in Hitler’s Germany. But they learned fast and so began months of hugely dangerous smuggling activity initiated by Krauss to help not only Jews but those in danger of falling foul of the regime. They made repeated short visits to Austria and Germany – sometimes flying sometimes by train to vary their route but always wearing unremarkable clothes and no coats, travelling home wearing jewels and fur coats they insisted were theirs but which they sold in order to help at least 29 families escape. Without financial guarantees refugees were not allowed into Britain. The smuggling was, she says, “a simple procedure.” But Nazi guards often boarded the train at the frontier for currency inspections and they risked death had they been caught.

Ida and Louise Cook were born at the beginning of the last century; Louise quieter and more intellectual in 1901; Ida chatty and confident – naturally garrulous – three years later in 1904 in Sunderland, Northeast England where their father, a Customs and Excise officer, was posted. The pair formed an intensely close bond from the cradle.  Both came to maturity during the harrowing years of World War One, a war which wiped out almost a generation of young men in England. The family moved around in the early years of the century and then settled in Northumberland where both girls went to school – The Duchess School – housed romantically in the old dower house of Alnwick Castle. They were clever children and perhaps realised intuitively that with the looks they were born with they were going to have to depend on their brains not their beauty to survive. By the time they moved back to London in 1919 – 24 Morella Road – they had two younger brothers, Jim and Bill.

Ida credits her parents, James and Mary Cook, as the source of all their good qualities, especially their courage. Or to use a contemporary word pluck. “Both parents set a standard of personal integrity that gave us children a never questioned scale of values and made life so much easier later on,” explained Ida.
One of the most appealing scenes of domestic tranquillity in her memoir has Ida describing to her mother how they had returned from a particularly harrowing experience. “I went straight through into the kitchen where mother was making pastry – which is after all one of the basic things of life … if she had stopped and made a sentimental fuss of me I would have cried for hours. She just simply went on making pastry… she told me ‘you’re doing the best you can. Now tell me all about it.’”  Such simple pleasures are hard to grasp in a post-feminist world. But from them derived the strength that allowed Ida and Louise to accept so unquestioningly the single life that was their lot but also their duty (another old fashioned word) towards others.

So as soon as they could, the two girls went out to work. Louise passed the civil service exams and became a clerical assistant in the Board of Education earning two pounds and six shillings a week and Ida followed her two years later. There is no mention of any young men ever. They just worked and paid a portion of their earnings to their mother for the room they shared perfectly content with what they had.
And then in the late 30’s, prompted by Clemens Krauss, they “stumbled” into Europe and began to save lives. “You never know what you can do until you refuse to take “No” for an answer,” Ida explained.

After the War Allied officials investigated Krauss’ pro-Nazi activities and for a while he was forbidden from appearing in public – until 1947. But his work with Ida and Louise played a key role in proving his innocence. He was able to show that he had frequently acted to assist a number of individual Jews escape the Third Reich. When his ban was lifted he resumed frequently conducting the Vienna Philharmonic, including its famous New Year’s Day concert and often stayed with Ida and Louise at the flat in south west London which they had bought but did not live in as it was given over to some of the refuges whose lives they had saved.

After the war life became tamer. Ida continued to write novels including the Oscar Warrender saga – tellingly a series about a girl who falls in love with a handsome conductor.
In 1967 as President of the Romantic Novelists’ Association she talked about the importance of romance in everyone’s life
“Cherish romance,” she said, “any fool can be a realist…of course any fool can also be a romantic,” she added, “but it was fortunate for this country that we were not led by a realist in 1940. If a realist had told us we were going to have a miserable time and asked if we could survive it we might not have done so. Luckily Churchill was one of the great romantics.”  Ida died on December 22 1986. Louise devastated survived until 1991. Earlier this year the Cook sisters were finally recognised as ‘British Heroes of the Holocaust’ and their families were handed a medal at 10, Downing Street in recognition of the part they played in fighting the Nazis.

Anne Sebba is the author of ‘Jennie Churchill – Winston’s American Mother’ and ‘That Woman – a life of Wallis Simpson’ to be published in August 2011 by Weidenfeld and Nicolson. She has written the introduction to Ida Cook’s Memoirs, Safe Passage (Mira Books)