The agency that would become MI5, originally known as the Secret Service Bureau, employed just 17 staff in 1914; by the end of the first world war, the number working for Britain’s domestic counter-intelligence agency had swelled to 850, including a number of female administrators.
While valuable for managing the card index records, noted Edith Lomax, the controller of women staff in 1918, only women under the age of 30 should be recruited “on account of the very considerable strain that was thrown on [their] brains”.
The merits of female intelligence staff remained a topic of debate within the agency. In 1945, Maxwell Knight, MI5’s leading agent-runner between the wars and reputedly the model for James Bond’s M, said while some believed women could not make suitable agents due to being “ruled by their emotions, and not by their brains”, “the emotional makeup of a properly balanced woman can very often be utilised in investigation … given the right guiding hand”.
He might have looked to the organisation’s early history during the first world war, when boy scouts were initially enlisted to run minor errands, only to be replaced by girl guides when they proved to be more reliable.
These and other fascinating tales – many stranger than fiction – make up a new exhibition about the history of the security service, opening this month at the National Archives in Kew, west London.
The exhibition is the first to be staged in collaboration with MI5 – whose very existence was only legally acknowledged in 1989 – and it features 20 remarkable and never before publicly displayed items loaned from the agency’s own Thames House archives.
These include the first camera used by the agency for surveillance, a tiny Houghton Ensignette, bought in August 1910 for £3.10 from the Army & Navy store on London’s Victoria Street, as well as one of the two monogrammed briefcases left by Cambridge spy Guy Burgess at London’s Reform Club before he fled to Moscow in 1951.
Visitors will also see a small pot of Yardley talcum powder, modified around 1960 by two KGB informants living in Ruislip, west London, to contain a microdot reader and several rolls of film.
On display, too, is a wizened 110-year-old lemon found in 1915 in a dressing table drawer at the home of Karl Muller, a shipping agent and supposed Russian refugee, whom the agency suspected of being a German spy.
Muller insisted he used the lemon for cleaning his teeth; in fact he had been using its juice as invisible ink, as was exposed when an agent ran a warm iron over an apparently innocent letter bound for Rotterdam, revealing a secret message detailing troop movements.
The exhibition has taken several years of collaboration between MI5 and the National Archives, the repository of Britain’s official records, which since 1997 has included 6,000 documents released by the secret agency.
Speaking at the launch of the exhibition, Sir Ken McCallum, MI5’s director general, said that having worked in the agency for almost 30 years: “I can tell you that the reality of our work is often different from fiction – whether that fiction is George Smiley or Jackson Lamb. MI5 life is about ordinary human beings together doing extraordinary things to keep our country safe. Some of their stories and their perspective comes through in this exhibition.
“While much of our work must remain secret, what you’ll see today reflects our ongoing commitment to being open wherever we can.”
Rather than merely endorsing the exhibition, MI5 had opted to collaborate fully, said Steve Burgess, head of events and exhibitions at the National Archives, with an unnamed MI5 co-curator adding commentary and previously undisclosed detail to the visitor information boards. “We’re absolutely thrilled because that has added a whole thread of a real MI5 voice throughout,” said Burgess.
“Where they were able to share, they were really generous,” he said. “They don’t often get to tell their story, given the work that they do. I think this is probably one of the first opportunities, and it’s a good platform to tell a complicated story.”
There were limits to MI5’s transparency, however. The criteria it used to make the loans was not disclosed, nor, inevitably, is there any information on what the agency has chosen to leave out. The most recent artefacts on display, which include a mortar shell fired into the garden of 10 Downing Street by the IRA in 1991, did not come from the MI5 archive.
Nonetheless, much of what is included is fascinating. Among the items on loan from MI5 are two tiny glass vials of quinine putty that Knut Brodersen, a Norwegian who parachuted into England as a Germany spy in 1944, had concealed in the eyelet holes of his leather boots. The putty was to be used to make invisible ink. Brodersen was caught and “the story was then extracted … under interrogation”, notes the unnamed MI5 commentator.
MI5: Official Secrets is at the National Archives in Kew from 5 April to 28 September 2025
