You didn’t mess with them – the doughty matriarchs of the intelligence world

As Hilary Mantel memorably noted, history represents what people try to hide, and researching it is a question of ferreting out what they want you not to discover. Claire Hubbard-Hall’s plan to unearth the identities and lives of the legions of women who have worked unheralded in the British secret services was bold: looking for secrets in a doubly secret world.

Miss Pettigrew was a ‘formidable grey-haired lady with a square jaw of the battleship type’

The first bureau was founded in 1909. It is perhaps not altogether surprising to learn that neither MI5 nor MI6 were very good to the female employees on whom they came increasingly to depend. Perceived as secretaries but given tasks unrecognisable in the normal secretarial world, young women were recruited in the first world war to organise and manage incoming secret messages, navigate a vast world of paperwork and in due course extract information from encrypted signals and captured documents.

Having signed the Official Secrets Act – official secrecy was defined in law only in 1911 – women were deemed by those in charge to be persevering and intuitive. They were credited with good memories and many seemed happy to work night and day. Unlike their male colleagues, they seldom left the office. Secret service work was ‘capital sport’, and agents – all men – hired their disguises from theatrical agencies.

Hubbard-Hall opens her book at a time when intelligence still involved pen and paper; she ends it in the era of sophisticated technology. Determined to find and describe as many individual women as she could, her book contains a vast cast of characters, many of whom flit only briefly across the page; but over the years, she suggests, they succeeded in shaping a matriarchal hierarchy in the world of intelligence.