You can make invisible ink from household items such as lemon juice, onion juice or milk, all of which become visible when heated. Other improvised sources are also available to agents in the field: when Mansfield Smith-Cumming ('C'), the eccentric founder of MI6, learned that semen made a perfect invisible ink - it's fluorescent under UV light - he declared: 'Every man his own stylo!’
More sophisticated inks need to be read using particular chemicals; the CIA has secured an exemption from disclosure for the formulae used in invisible inks during the First World War, on the grounds that these are still a matter of national security.
You can also buy invisible ink printer cartridges, which are used for various applications such as routing instructions on mail and tracking information on leaflets.
Israel’s Institute of Science and Halacha (the legal interpretation of the Talmud) has developed ink that fades over the course of a few days so that Jewish doctors can write prescriptions on the Sabbath; they aren't allowed to create anything permanent, but a temporary document is permissible.
The ink used to sign birth certificates is designed to do the opposite of becoming invisible; rather than fading it becomes blacker with age.
I’ve always wanted to be a spy, and frankly I’m a little surprised that British intelligence has never approached me.
MI5 employee Michael Bettaney once attempted to avoid a ticket inspector on a train by shouting ‘I’m a spy!’
MI5 considered north Wales the ‘safest place’ to hide its double agents in the event of a German invasion of Britain.
John Major first officially admitted MI6’s existence in 1993. MI6 has the responsibility for conducting operations in support of UK foreign policy objectives and to counter threats to the UK's national security on a world-wide basis.
In recent years MI5 and MI6 have embraced a more transparent public persona. While the very existence of the services used to be denied, today the location of their head offices is widely available and staff members give interviews and write books. Not everything has changed though: in 2008 an MI6 officer was interviewed on the One Show but proceedings were interrupted when his moustache fell off halfway through.
Although only MI5 and MI6 remain, there were ten Military Intelligence sections during the First World War and 17 by the time the Second World War finished. MI1 looked after codes and ciphers; MI4 was maps; MI12 organised censorship; MI16, formed in 1945, dealt with scientific intelligence. There was never an MI13.
MI5 estimates there are as many Russian agents in London now as there were at the height of the Cold War.
MI5 considered using a team of highly-trained gerbils to detect spies and terrorists flying into Britain during the 1970s.
‘C’ was the code name of Sir Mansfield Cumming (1859-1923), the founding director of MI6. He came to be known as ‘C’ after his habit of initialling papers he had read with a C written in green ink, a tradition carried on to this day by MI6 Chiefs.
Sir Mansfield joined the Navy in 1878 and was posted on HMS Belleraphon on which he served for seven years in the East Indies. In 1885 he was placed on the retired list for seasickness and listed as 'Unfit for service'. He was recalled to work in the foreign section of Naval Intelligence in 1898 and undertook many missions including one which took him to Germany and the Balkans, where he pretended to be a German businessman despite the fact that he didn’t speak any German.
He was so successful he was recruited to the Secret Service Bureau (SSB) as director of the foreign section. In 1911 he was placed in command of the SIS’s (Secret Intelligence Services) foreign section which dealt with all operations outside of Britain. It was during the First World War that the SIS became MI6.
Cumming lost a leg after a car accident in France that also killed his only son, Alistair. There are many versions of the story of how his leg was amputated, including one that claims he amputated it himself using a pocket knife. He would whip around the corridors of MI6 with a scooter supporting his wooden leg. He was renowned for emphasising his points in an argument by stabbing his wooden leg with a paper knife.
The ‘real’ James Bond was an ornithologist and the author of the magisterial reference book, Birds of the West Indies.
Ian Fleming, a keen twitcher living in Jamaica at the time, commented: ‘I wanted the simplest, dullest, plainest-sounding name I could find, and “James Bond” was much better than something more interesting, like “Peregrine Carruthers.”'
Fleming referred to Bond as a ‘secret agent’. This term has never been recognised officially: members of the intelligence services are ‘officers’ while assets in the field are ‘Covert Human Intelligence Sources.’ MI5 also strenuously deny having a ‘licence to kill.’
In the books, James Bond has a drink every seven pages on average and whilst he does consume 19 vodka martinis, his favourite drink is whisky which he drinks 101 .
The first rule in keeping secrets is nothing on paper... if you really want to keep something secret, don’t write it down
British intelligence chiefs tried to guess Hitler's plans by studying his horoscope.
The last execution in the Tower of London took place in 1941, when Josef Jakobs, a German spy, was shot by firing squad.