Plans to withdraw Ministry of Defence (MOD) staff from a tracking station on the island of St Kilda have been met with concern by the National Trust for Scotland (NTS).

The trust said that the MOD's decision to switch to a remote control system could cost millions in ongoing conservation costs, while annual running costs for the island are set to increase by more than £500,000. NTS would also incur additional costs relating to the repair or removal of buildings that are currently leased by the MOD, which has had staff stationed on the island since 1957 and shares power, water and transport services with the trust.

Michael Hunter, NTS director of properties and visitor services, said: "As a charity, we would struggle to find the extra funds needed to cover the costs of running operations on St Kilda. Inevitably, we would look to public bodies to help support us in our vital work to protect and preserve this wonderful place for the benefit of everyone. "The trust remains open to dialogue and discussion and we very much hope that we can work with the MoD to find a solution which recognises the importance of St Kilda for Scotland and the world, and the important role that our charity plays in conserving that for future generations.

St Kilda is the only Mixed World Heritage Site in the UK, designated for both its natural and cultural significance. The island is also home to one of the north-east Atlantic's most significant seabird colonies.