Every good lawyer knows that client confidentiality is sacred, but sometimes they forget just who’s listening. Many’s the time Lawyer 2B has picked up a good bit of gossip from listening to two trainees chatting away on the train. So you would have thought Donald Trump’s lawyers, involved in one of the most explosive investigations of recent times, would know how to keep their mouths shut.

Apparently not. The lawyers in question, former Hogan Lovells partner Ty Cobb and and former Akin Gump partner John Dowd, were caught discussing the probe into Trump’s Russia connections loudly over lunch in a restaurant by a New York Times reporter sitting at the next table.

Worse, Cobb revealed that there are pertinent documents that one of his colleagues, Don McGahn, is keeping “locked in a safe” rather than disclosing to the Special Counsel leading the Russia investigation Robert Mueller.

Catastrophic breaches of client confidentiality are constant hazard in the law. The last high profile one in the UK was in 2013, when media firm Russells Solicitors has to issue a grovelling apology after JK Rowling was outed as Robert Galbraith, author of detective novel The Cuckoo’s Calling. One of the firm’s partners had let the information slip to his wife’s best friend, who then leaked it to the Sunday Times. He was eventually fined £1,000 for breaching privacy rules, while Rowling accepted an apology from the firm and damages in the form of a donation to charity.