Prime Minister Benjamin Netanyahu may have planted a listening device in the bathroom of Britain’s ex-premier Boris Johnson when visiting the then-foreign minister’s office in 2017, according to an excerpt from Johnson’s upcoming memoir obtained by British media.

Quoting the excerpt from “Unleashed,” which is set for release later this month, The Telegraph reported Thursday that Netanyahu, then on his first-ever visit to the London office, asked to use the bathroom that Johnson describes as similar to “the gents in a posh London club” which exist within a “secret annex.”

“Thither Bibi repaired for a while,” writes Johnson, referring to the premier by his nickname, “and it may or may not be a coincidence but I am told that later, when they were doing a regular sweep for bugs, they found a listening device in the thunderbox.”

The Telegraph said it was unclear whether Israel was at all confronted over the incident.

Asked for further comment, Johnson told The Telegraph: “I think everything you need to know about that episode is in the book.”

The newspaper noted that not long after the episode relayed by Johnson, Israel was accused of bugging the White House, in a 2019 Politico report that cited three former United States officials. Netanyahu, at the time, denied the report, and then-US President Donald Trump also said called it “hard to believe.”

London has also been accused of spying on Israel’s government and missions abroad, based on leaked US intelligence obtained in 2016 by French newspaper Le Monde.

In his upcoming memoir, Johnson also recalls kidding Netanyahu during the Israeli premier’s visit to the British Foreign Office.

According to The Telegraph, Netanyahu was “awestruck” when showed the walnut desk in Johnson’s office, which the former premier said at the time was the one used by former British foreign minister Arthur Balfour to write the 1917 Balfour Declaration, which proclaimed London’s commitment to the Zionist cause of founding a Jewish state.

In fact, Johnson is said to confess in his memoir, he has no idea where or how Balfour wrote the declaration, but it was unlikely at that desk.

Johnson also reportedly recounts having claimed to possess the very pen with which Balfour wrote the declaration — only to delve into his would-be Zionist relic of a desk and produce a store-bought Bic pen.

Johnson, 60, served as Britain’s foreign minister between 2016 and 2018, and then as prime minister from 2019 to 2022, when he was forced to resign over accusations he had flouted COVID-era restrictions enforced by his own government.

The colorful conservative politician — a sharp-tongued former journalist trained in the classics — has been stridently pro-Israel throughout his career, and continues to strike a pro-Israel tone in his regular column in the right-leaning Daily Mail.