British lawyers and their client's secrets.

Season 2 Episode 3 depicts Eileen Parker going to a lawyer to sue her husband (the Duke's secretary) for divorce. As soon as she leaves the lawyer's office he picks up the phone; it is revealed that the lawyer told someone who in turn told the Queen's secretary about her intention to divorce her husband. Even later after she brought evidence of her husband's infidelity to the lawyer, the lawyer kept others appraised of his client's case.

So was lawyer client confidentiality something to be expected in England back in the 1950's? I understand that a divorce in England required a public trial, but are the lawyers still expected to keep their clients secrets?