In the Falklands war, the BBC broadcast that the Argentine air force were setting their bomb fuses wrong and their bombs weren't exploding when they hit British ships, and also pre-announced the attack on Goose Green. They're well known for playing both sides against the middle.

I have read that the Goose Green incident was actually caused by a MoD official releasing something too early - they were just passing on the message.

The thing about the bomb fuses was a horrendous mistake “six better fuses and we would have lost” - particularly as there was nothing wrong with the fuses and the Argentinians could have easily fixed this by a simple adjustment.