Some of the more elaborate diaries take years to crack
There is a certain thrill to cracking a code.
The 300,000-word journal of Charles Wesley, the co-founder of the Methodist movement, which was written in an obscure shorthand, has been solved and the diary transcribed. It has taken nine years.
It appears that the shorthand was used not for speed, but for security. What was so important that it required the secrecy of a complex code?
Wesley's is not the only diary that has used a code, however, with everyone from Beatrix Potter to British prisoners of war using their secret diaries to express feelings that no-one else was meant to understand.
Charles Wesley, the co-founder of the Methodist movement, produced 1,000 pages of hand-written manuscript over his life.
The 300,000 words detailed the darker sides of his thinking - which is why he chose to hide them in a secret script.
The diaries reveal previously unknown information, including a sex scandal. Wesley wrote that after joining his brother John in an American colony, he fled home amid allegations that he had intercourse with a colonist after trapping her husband under a tree.
The transcription took nine years to complete. Professor Kenneth Newport, pro vice-chancellor of Liverpool Hope University, deciphered the pages written 250 years ago between 1736 and 1756.
He solved the code after discovering Charles had also transcribed gospels from the King James Bible in the same way.
He said that the shorthand was so difficult to understand "because Wesley abbreviated so significantly". Vowels were removed and consonants were shortened. Even after the literal transcription was made, it was still very difficult to understand.
Prof Newport explains that the reason he stuck with it was because he got quite caught up with the process, and by the time he realised, it was not worth turning back.
Monday 22 March, 1736
"While I was persuading Mr Welch not to concern himself in this disturbance, I heard Mrs Hawkins cry out: 'Murder!' and walked away.
"Returning out of the woods, I was informed by Mr Welch that poor blockhead Mrs Welch had joined with Mrs Hawkins and the Devil in their slanders of me. I would not believe it till half the town told me the same, and exclaimed against her ingratitude."
Donald Hill used his wife's name in his cleverly-constructed encryption
Donald Hill was in the RAF, attached to the Far East command in Kai Tak, Hong Kong, during World War II. The Japanese attacked on 8 December 1941 and after surrendering, he was put into a prisoner of war camp.
The diary he made was hidden as a maths table. He would have been killed if he had been found writing it. The entries talked about what it was like to be attacked and then to be a prisoner of war.
The diary only came to light after Hill's death in 1985, when his wife Pamela was desperate to learn of a time that he had not discussed with her. After historians had attempted to decode it, in 1996 it was given to Philip Ashton, a mathematician at Surrey University.
He was amazed at the complexity of the code, and six months were spent experimenting with a variety of trial and error techniques until he remembered reading the full names of the two lovers, Donald and Pamela, at the bottom of the page.
The diary entries were meant to look like a multiplication chart
By putting these names over the grid, a pattern emerged and the diary was transcribed.
"Two officers decide to drive me back in a Ford Ten. They don't use any lights and we have several narrow escapes from hitting lamp posts. Suddenly I see we are heading for one of the islands in the middle of the road and shout a warning.
"Too late and there's a terrific crash and we finish up on our backs. By now I am fed up so, bowing politely, I leave them and walk the two miles to China Command."
Beatrix Potter's diary became more difficult to read in later entries
The children's author Beatrix Potter wrote diaries throughout her life, though as soon as she started publishing her work these entries ended. Her younger diaries were written in code.
The only surviving entries of this diary are between 1881 and 1897. Unlike other secret diaries - which held secrets that could ruin careers or cost lives - this diary was personal, expressing feelings that she wished to hide.
It is commonly believed that the code was to save it from being read by her mother, with whom she did not have a good relationship.
But Emma Laws, the Frederick Warne curator of children's literature at the Victoria and Albert Museum, thinks differently.
Potter altered letters to make her code - courtesy of the Warne Archive
"A lot of things in the diary would not be seen as right for a Victorian girl to mention. It contained much bitterness and disappointment," she says.
Ms Laws admits however, that no-one can ever be quite sure. "It could also be her imagination. There is sense of creativity devising a code."
The code was cracked by Leslie Linder, a lifelong collector of Beatrix Potter artefacts. The documents were not found until the middle of the 1950s, and the mystery was not solved until 20 years after Beatrix's death: on Easter Monday 1958.
Tuesday 17 November, 1890
"I remember I used to half believe and wholly play with fairies when I was a child. What heaven can be more real than to retain the spirit-world of childhood, tempered and balanced by knowledge and common-sense, to fear no longer the terror that flieth by night, yet to feel truly and understand a little, a very little of the story of life."
Lord Hailsham describes "indecisive, divided" cabinet ministers in his diary
Lord Hailsham, former Lord Chancellor and Conservative minister, wrote a diary towards the end of his career, detailing secrets and anecdotes of the Conservatives in the 1970s.
Lord Hailsham, when speaking in his memoir A Sparrow's Flight, condemned political diary-keeping and said that nothing of the kind would be found in his papers.
Ironically, he kept the only diary that has been found of the Conservative cabinet meetings.
It told of meetings attended while Lord Chancellor. He was frank with his opinions, assuming his code would never be broken. The parts currently translated include an account of the disagreements with the National Union of Mineworkers and the mining strike of 1972.
Most of the entries are in speedwriting, a phonetic system of abbreviation or word-contraction invented in the US in the 1920s, which he modified over the years. This made even experienced speedwriting teachers unable to read the journals reliably.
A number of the coded entries have been translated with the help of cryptanalysts at GCHQ, working in their spare time. But the Margaret Thatcher Foundation has appealed for help in translating the remainder of the diaries.
"An odd story of the 1964 election never published. Alec (then Prime Minister) was staying with John and Priscilla Tweedsmuir - who had no room for Alec's private bodyguard. He went to the nearest town (Aberdeen?) and John & Priscilla left Alec for a time alone in the house.
"Knock at the door. Door answered by PM in person. Deputation of left-wing students from Aberdeen University. Said they were going to kidnap Alec. He: 'I suppose you realise if you do the Conservatives will win the election by 200 or 300.'
"He asked and received permission to pack a few things & was given 10 mins grace. After that they were offered and accepted beer. John & Priscilla returned and the kidnap project abandoned. The bodyguard swore Alec to secrecy as his job would have been in peril."
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