Breaking German code vital to D-Day

After the war she wrote books, became fierce defender of garden heritage

Mavis Batey, who has died aged 92, was one of the leading female codebreakers at Bletchley Park, cracking the Enigma ciphers that led to the Royal Navy’s victory at Matapan, its first fleet action since Trafalgar.

Perhaps fittingly, she died on Remembrance Day.

She was the last of the great Bletchley “break-in” experts, those codebreakers who found their way into new codes and ciphers that had never been broken before.

Batey also played a leading role in the cracking of the extraordinarily complex German secret service, or Abwehr, Enigma. Without that break, the Double Cross deception plan that ensured the success of the D-Day landings could never have gone ahead.

Mavis Lilian Lever was born in Dulwich, south London, on May 5, 1921, the daughter of a postal worker and a seamstress. The family always went on holiday to Bournemouth, but after studying German in secondary school, Mavis persuaded her parents to take her to the Rhineland.

It was this that encouraged her interest in the German Romantic poets. She was studying German at University College, London, when war broke out, and decided to break off her studies and become a nurse. But she was told the country could make more use of her as a German linguist.

“So I thought, great,” she recalled. “This is going to be an interesting job, Mata Hari, seducing Prussian officers. But I don’t think either my legs or my German were good enough because they sent me to the Government Code & Cipher School.”

She initially worked in London, checking commercial codes and perusing the personal columns of The Times for coded spy messages. After showing promise, she was plucked out and sent to Bletchley Park to work in the research unit run by Dilly Knox.

Knox had led the way for the British on the breaking of the Enigma ciphers, but was now working in a cottage next to the mansion on new codes and ciphers that had not been broken by Hut 6, where the German army and air force ciphers were cracked.

“It was a strange little outfit in the cottage,” Mavis said. Knox was a true eccentric, often so wrapped up in the puzzle he was working on that he would absent-mindedly stuff a lunchtime sandwich into his pipe rather than his tobacco:

“Organization is not a word you would associate with Dilly Knox. When I arrived, he said, ‘ Oh, hello, we’re breaking machines, have you got a pencil?’ That was it. I was never really told what to do. I think, looking back on it, that was a great precedent in my life, because he taught me to think that you could do things yourself without always checking up to see what the book said.

“That was the way the cottage worked,” she said. “We were looking at new traffic all the time or where the wheels or the wiring had been changed, or at other new techniques. So you had to work it all out yourself from scratch.”

After the war Mavis Batey brought her indefatigability to the protection of Britain’s historical gardens.

She became the driving force behind moves by the Campaign for the Protection of Rural England, English Heritage and the Garden History Society to protect historical gardens.

Working with the Historic Buildings Council, she instigated the formal recording of historic gardens, which led to the publication of English Heritage’s Register of Parks and Gardens of Special Historic Interest in England in 1984.

She was awarded the Veitch Memorial Medal of the Royal Horticultural Society in 1985, and in 1987 was appointed MBE for services to the preservation and conservation of historic gardens.

Her books included Jane Austen and the English Landscape (1996); Alexander Pope: Poetry and Landscape (1999); and an affectionate biography of Knox, Dilly: The Man Who Broke Enigmas (2011).