M, 3 Stars

This handsomely produced American film is set in Europe during World War II, when things were going badly for the Allies. It was looking likely Hitler's forces would cross the Channel at any minute.

A Call to Spy was filmed in Philadelphia and Budapest, locations posing as France and London, with subterfuge that seems entirely appropriate to a tale about espionage.

Based loosely on the remarkable facts, it is about women who became British spies early in the 1940-41, when Britain's prospects of survival had hit rock bottom. The British did not send women into the field, until then.

Some gutsy and dedicated women responded to Churchill's call for women to join a "secret army" working undercover in Nazi-occupied Europe.

This was the same organisation to which Nancy Wake, the "White Mouse", belonged. This is also a story that isn't a million miles from the film Charlotte Gray, released in 2001 with Cate Blanchett's character a blend of famous female spies.

A Call to Spy is directed by Lydia Dean Pilcher, whose filmography mostly includes production credits. Her direction is fine, and the high production values have contributed to convincing sets and costume that evoke the wartime period well enough. However, there are other weaknesses to this, a story whose telling is long overdue.

The main character here is Virginia Hall, a woman who lived for danger. She was American, a brave woman who tried to enter the US foreign service but was rejected because of her disability, a wooden leg that was the result of a hunting accident.

Hall eventually opted for espionage, joining up to Churchill's Special Operations Executive that worked in the field with the French Resistance. It was sometimes dubbed the "Baker Street Irregulars" because of its clandestine existence. Post-war, Hall slipped into the obscurity she seemed to choose, but received medals for outstanding service including the French Croix de Guerre. A glance at the Smithsonian entry about her online confirms her extraordinary wartime record. Her prosthesis, a wooden leg known as "Cuthbert", has even been honoured.

She tried again to become a diplomat, but eventually joined a newly formed agency known as the CIA, where she became one of its key operatives. Here she is played by actor Sarah Megan Thomas, also the writer of the screenplay.

In addition to Hall, the central character, there is another woman of great potential interest, Noor Inayat Khan, a pacifist Sufi Muslim who joined the SOE as a very able radio operator. Noor, played by Radhika Apte, is described as the daughter of the man who introduced Sufism to the West. She showed exceptional courage during Gestapo torture and was eventually shot in Dachau.

Noor was the first radio operator to be sent into occupied France. Postwar, she became the first Muslim female to be decorated as a British war hero. She was awarded the highest civilian medal, the George Cross.

These facts are all extraordinary. So why, with such a scintillating backstory, is the film rather bland and low on dramatic tension? The writing is pedestrian and there is little that shows how remarkable these women, and Vera Atkins (Stana Katic), who recruited them, were.

Unfortunately, there are too many moments when the performances of key characters don't ring true. Apte as Noor and Thomas as Virginia and many others are fine but there are scenes between Katic's Atkins and Linus Roache's Maurice Buckmaster, her boss, that let the ensemble down. Very clunky performances.

The writing needed more research built into it to make clear the significance of these women and their unique stories. There is instead a screed of stunning facts left for the very end, before the final credits. The historical background is riveting and I wish I could say the same of the film.

This true tale of women spies has managed to beat the new James Bond, basely entirely on fantasy, to cinema screens.

Another, better, film may come along that does a better job of telling this remarkable story.