Manchester United boss Sir Alex Ferguson admits he's concerned over reports of England's training camp being bugged.

Ferguson and Manchester United were at the centre of a similar controversy in 2005 when listening devices were found in the home dressing room at Old Trafford after a key encounter with Chelsea.

And, ahead of a World Cup campaign, he thinks the latest development is a worry.

"It happened to us once before," he said. "I would be concerned about it. You have to be. Preparation involves discretion and secrecy. I haven't revealed one bit of my tactics ahead of the AC Milan match. I haven't been asked. And do you know why? Because I wouldn't tell anyone.

"Why should I tell anyone?

"Capello may have been discussing some important issues about his team. All of a sudden someone else has got it.

"It is a concern."