Herbert Asquith ‘had passionate weekly trysts with aristocrat in back of car’

Herbert Asquith had passionate weekly trysts with his mistress socialite in the back of his official prime ministerial car, author Robert Harris has claimed.

The risky affair of the Liberal prime minister (1908-16) with aristocrat Venetia Stanley – who was 35 years his junior – contributed to a series of military and political crises at the onset of the First World War.

Piecing together information from Asquith’s letters to Stanley while doing research for his new book, Precipice, Harris found the married father of seven was smitten with his young mistress.

He also discovered that Asquith shared state secrets during their trysts, with copies of classified documents later handed over to police after being discarded from his car.

The major breach of protocol was revealed by Asquith’s prolific letter writing.

During the height of their affair, he was writing to Stanley three times a day and organised Friday afternoon drives in the sealed compartment of his state car, a 1908 Napier.

“It has always been suggested this was more of a fantasy relationship than a real love affair,” Harris told The Observer newspaper.

“But there are paragraphs left out of his published letters to her that indicated it was much more.

“He wrote notes to Venetia, then in her late 20s, during crucial Cabinet meetings and clearly sought her advice, as well as sending her love poetry – lines from Tennyson and Browning.”

Harris’s new book claims the relationship was physical.

Speaking to The Sunday Times about the prime ministerial car, he pointed out there was a “fixed glass screen between the driver and the passengers, with a curtain. Blinds on all the other windows. You communicate with the driver by console … It’s a bedroom on wheels. No wonder they went driving around for an hour and a half, seemingly aimlessly”.

The book claims Asquith breached major protocol by sharing vital military secrets and coded documents with his mistress – and failed to recall important information about army ammunition supplies because Stanley was in possession of the key briefing document.

“I became fascinated by this aspect of Asquith’s story,” Harris told The Observer.

“We can account for so much of his time in the run-up to the First World War, but this enabled me to tell the story day-by-day through the 560 letters Venetia kept.”

A 1964 biography of the former prime minister by Roy Jenkins downplayed his affair with Stanley, with Asquith’s former wife Margot and daughter Violet playing down her temptress qualities, describing her as “plain”.

Anna Mathias, Stanley’s granddaughter, told The Observer she was “completely delighted” by Harris’s work.