[Pokey78]

. . . and circulated to both senior agents in his organisation and to a friendly foreign intelligence agency . . .

Most likely leaked by someone in the "friendly foreign intelligence agency"; my guess being MI6.

[Just mythoughts]

so the leak says. Far more value to leak what information was gained.

When a leak happens the whole picture must be looked at to see the purpose of a leak. Leaking that this is being done does not look positive on the President, leaking was was found out would put people on the spot and on the defence.

The story does not paint a positive picture of bugging, so why leak it?