LONDON, Jan. 6 (Xinhuanet) -- British Transport Secretary AlistairDarling said Tuesday that Britain's controversial sky marshals plan will go ahead, saying they will be deployed when appropriate for security reasons.

    Speaking in British parliament, Darling said "we announced sky marshals plan in 2002" and the use of the marshals on commercial flights is a "responsible and prudent step at the present time".

    But he said the government will not reveal when and where the marshals are operating, but they will be used "when appropriate".

    "There is an increased threat and we have to deal with that in a balanced and proportionate way," he added.

    Darling said the state of alert will last for a considerable time.

    British government's plan to deploy sky marshals on planes has met with opposition from the British Association of Airline Pilotswhich told Darling that air marshals are a threat to safety.

    General Secretary Jim McAuslan of the association said the use of sky marshals to minimize the threat posed by terrorists simply introduces another risk.

    Darling said Tuesday that discussions over whether to deploy air marshals with pilots have taken place and he assured that pilots will still be in charge of the plane even if air marshals are deployed.

    The Unites States has insisted they should be deployed on some transatlantic flights. Enditem