LONDON, July 31 (Reuters) - A dual British-Azerbaijani national has been arrested in Cyprus on suspicion of spying on a British air base on the Mediterranean island and passing information to Iran's Islamic Revolutionary Guard Corps, London police said on Friday.

Rashad Sultanov, 44, from Islington in north London, was arrested on July 17 by Cypriot authorities and is being held in custody as extradition proceedings progress, the Metropolitan Police said in a statement.

He was arrested as part of Britain's first overseas National Security Act investigation, led by counter-terrorism police into incidents at Britain's RAF Akrotiri base in Cyprus between May 11 and June 22 last year, the statement said. Cypriot police did not immediately return a request for comment.

Sultanov allegedly conducted hostile surveillance on the base and is alleged to have then shared information with the IRGC, the British police added.

"This case shows we are able to use the National Security Act overseas when British military bases are allegedly targeted by hostile state activity," Helen Flanagan, head of counter-terrorism policing in London, said in the statement.

The IRGC threatened earlier this month to attack any British military bases used by U.S. forces to launch attacks on Iran.

An Iranian-type Shahed drone caused slight damage on March 2 when it hit facilities at Akrotiri. Soon afterwards, Britain said the base would not be part of its defensive agreement with the United States over the use of UK bases.

Also in March, Iran was reported to have fired two ballistic missiles at a U.S.-UK military base on Diego Garcia in the Indian Ocean, though neither hit the target.

Akrotiri is one of two bases Britain has retained in its former colony since independence in 1960. It has been used for past military operations in Iraq, Syria and Yemen.

(Reporting by Muvija M in London; Additional reporting by Michele Kambas in Nicosia;Editing by Helen Popper)