The BBC has apologised to the Queen for revealing that she once spoke to the home secretary about the radical Muslim cleric Abu Hamza, asking the government why he could not be deported.

The report of the Queen's intervention was made by security correspondent Frank Gardner on this morning's Today Programme on Radio 4.

The disclosure immediately made headlines but, within hours, the BBC released the following statement: "This morning on the Today programme our correspondent Frank Gardner revealed details of a private conversation which took place some years ago with the Queen.

"The conversation should have remained private and the BBC and Frank deeply regret this breach of confidence. It was wholly inappropriate. Frank is extremely sorry for the embarrassment caused and has apologised to the Palace."

On Monday, Abu Hamza lost an appeal to the European Court of Human Rights against his extradition to the US, the latest development in a legal battle that has been running since the 1990s.

On the Today programme this morning, Gardner said: "The Queen was pretty upset that there was no way to arrest him. [She said] surely there must have been some law that he'd broken... why is he still at large?"

Today host James Naughtie, audibly stunned, replied: "That's a fascinating piece of information, Frank!"

"Yes I thought I'd drop that in. She told me," Gardner slightly hesitantly added.

"Drop it in?!" Naughtie continued. "That's a corker!"

Listen to the Today report here:

listen to ‘Queen told BBC man she was 'upset' Hamza could not be arrested’ on Audioboo