Manchester United are hunting a mole who bugged their team dressing room, the club confirmed yesterday.
A radio transmitter was planted in the home team's changing area during the crucial match against Chelsea last week. Sir Alex Ferguson's match tactics and team talk were taped by the mole tuning in to the bug's frequency.
Phil Townsend, the club's head of communications, confirmed an investigation was under way. The spy could also face a police inquiry.
The sting operation came to light after The Sun newspaper was offered the taped conversations for cash by a middle man.
Mr Townsend said: "We have launched our own investigation and if necessary will involve the police." He said the investigation was still in its "early stages".
The club has a museum and stadium tour which attract 200,000 visitors a year. The tour includes a visit to the home dressing room - even on match days.
The tapes were recorded last Sunday when Manchester United ended Chelsea's 40-match unbeaten run with a 1-0 victory.
They include pre-match and half-time team-talks, plus the celebrations of jubilant players as they congratulate each other after coming off the pitch.
On the tapes Sir Alex Ferguson can be heard encouraging his players and giving tips to Wayne Rooney and Ruud van Nistelrooy, according to The Sun.
After the final whistle jubilant United players troop back into the dressing room where they can be heard congratulating each other and urging one another to maintain their winning form.
Defender Rio Ferdinand also asks a team mate about his plans for the evening. The players cheer as Sir Alex swears during a live TV interview. The appearance of controversial Chelsea coach José Mourinho on TV is met with derision.