Storm repairs to St Kilda kirk famous for WW1 U-boat attack

St Kilda Kirk requires extensive work to its roof and gutters

Storm repairs and conservation work are being carried out on a 200-year-old church on Scotland's remote St Kilda archipelago which famously came under attack from a German U-boat during World War One .

National Trust for Scotland (NTS) is using specialist contractors to make the old kirk and a historic school building next door wind and watertight.

St Kilda - more than 40 miles (64km) west of the Western Isles - is hit by gale-force winds about 75 days a year with some gusts reaching 144mph, according to NTS.

The kirk was damaged in 1918 during an attack on the islands by a German submarine, before later falling into ruin after the last 36 islanders abandoned St Kilda in 1930.

Workers carrying out repairs to the kirk's roof

The church, which is on the main island of Hirta, was restored in the 1970s.

It now needs extensive repairs to its roof and gutters as part of a first phase of conservation costing more than £200,000.

A Historic Environment Scotland grant and donations from the trust's members and supporters have helped cover the cost.

St Kilda has dual Unesco World Heritage status due to the importance of its heritage and wildlife, including thousands of sea birds.

Traditional masonry techniques are being used in the repairs.

All the materials brought to Hirta from the mainland have to be checked for stowaway non-native species of animals, such as rats which could prey on ground-nesting birds.

Susan Bain, NTS property manager for St Kilda, described the project as "a gruelling logistical marathon".

She added: "Working in the middle of a dual World Heritage Site has its challenges and noise must be kept to a minimum to avoid disturbing wildlife or visitors."

Dozens of shells were fired at buildings on Hirta during the German attack in May 1918 and the kirk was damaged.

Deliveries of materials are checked for stowaways before being taken by boat to St Kilda