Taiwan plans to bring home from Britain a young military intelligence officer after she failed to return to the island last year, officials and media said Thursday.

Yeh Mei, a lieutenant with Taiwan's Military Intelligence Agency, took an overseas sightseeing trip in June last year but for unknown reasons did not return for duty. Since then she has been placed on a wanted list by a local court.

Yeh was detained by the UK Border Agency last week for overstaying her visa and her attempt to extend it was rejected, the state Central News Agency said, adding that she has been sent to an immigration removal centre.

"We're working together with the foreign ministry to escort her back to Taiwan," defence ministry spokesman David Lo told AFP.

Taiwan and Britain have no diplomatic ties or extradition treaty. Lo said China, contrary to speculation, had not played any role in Yeh's movements.

"Some local media had said she defected to the Chinese mainland, which was not true. The Military Intelligence Agency attributed her move to 'personal factors'," Lo said.

China still claims Taiwan as part of its territory awaiting reunification, by force if necessary, even though the two sides have been governed separately since the end of a civil war in 1949.

Ties have improved markedly since Ma Ying-jeou of Taiwan's China-friendly Kuomintang party came to power in 2008. He was re-elected in January 2012.

But the former arch-rivals still spy on each other. In 2012 Taiwan's top court rejected an appeal by former army general Lo Hsien-che, who was jailed for life in the toughest punishment meted out in an espionage case in decades.

He was suspected of handing over to China information relating to a project that gave the Taiwanese military some access to US intelligence systems.