The Supreme Court has handed down judgment in a case brought by Ingenious Media Holdings plc and its CEO, Patrick McKenna, against HMRC for breach of confidentiality.

Back in 2012, an HMRC official gave an off the record interview to two journalists from The Times, in which he made a number of remarks about tax avoidance film and investment schemes promoted by Ingenious, and about Mr McKenna in particular. The official appears to have been under the misapprehension that because the interview was off the record he could say what he liked. Unsurprisingly, the information he provided and his views finished up in the paper.

The claim did not succeed in the High Court, nor in the Court of Appeal. But it succeeded in the Supreme Court, which has reaffirmed that a person's tax affairs are confidential as between that person and HMRC, and may not therefore be disclosed to any third party, even on a confidential or off the record basis:

"An impermissible disclosure of confidential information is no less impermissible just because the information is passed on in confidence; every schoolchild knows that this is how secrets get passed on."

The Court was very clear that "a general desire to foster good relations with the media or to publicise HMRC's views about elaborate tax avoidance schemes" could not justify discussing the affairs of individual tax payers with journalists.

Nor was it impressed by HMRC's defence that the official had not anticipated his comments being reported on the basis that they were provided off the record:

"The whole idea of HMRC officials supplying confidential information about individuals to the media on a non-attributable basis is, or should be, a matter of serious concern."

The decision is a salutary reminder of the willingness of the English Courts to protect confidential information. It is also timely, given a number of recent and unlawful disclosures of the tax affairs of individuals and businesses.

And it's a reminder of the need to be careful about what is said to the media on an off the record basis. A useful rule of thumb is not to say anything off the record which you would not be happy to see in print.