The country has been fearful of further attacks since four British Islamic militants blew themselves up and killed 52 passengers on the London transport system in July.

Police would not say what sort of group they targeted in the raids, conducted with help from the Security Service also known as MI5, although they did say the investigation was separate from the inquiry into the London bombings.

A police spokeswoman would only confirm the arrests were not linked to Irish republicanism. She would not specify the nationality of those arrested.

Intelligence

Three men were arrested in the Croydon area of south London while seven were arrested in the English Midlands - four in Wolverhampton and three in Derby, a police statement said.

"At approximately 4am today police executed warrants at three residential addresses, making a total of 10 arrests, all on suspicion of the commission, preparation or instigation of acts of terrorism under the Terrorism Act 2000," it said.

"The arrests were made as the result of an intelligence led investigation involving police and the Security Service."

Police were searching the three locations raided, the statement said.