Relatives of those who lost their lives when a Royal Navy battleship was blown apart in Orkney are to take part in a special commemoration service on the islands.

A series of internal explosions destroyed HMS Vanguard on the night of July 9 1917.

Just two of the 845 men on ship, which was anchored at Scapa Flow, survived.

Military experts say the loss of Vanguard, a dreadnought battleship which had been involved in the Battle of Jutland, is one of the most tragic incidents in the history of the Royal Navy.

Hundreds of casualties will be remembered on the centenary of the sinking of the vessel.

Relatives of some of those who died will be among those taking part in the commemorative events on July 9 this year.

These will be preceded by a musical concert in St Magnus Cathedral in Kirkwall on July 8, performed by an ensemble and Corps of Drums from the band of Her Majesty's Royal Marines.

The wreath-laying service involving two modern-day Royal Navy vessels will be held above the wreck of the Vanguard, which lies in 14 metres of water to the north of the island of Flotta.

It will be followed by a service at the Lyness Royal Naval Cemetery in Hoy, where 41 of the ship's crew were buried.

Later in the evening there will also be a watch night service at St Magnus Cathedral at 11pm to mark the moment the ship went down.

Brian Archibald, head of marine services, engineering and transportation with Orkney Islands Council, said: "These will be very poignant events.

"They offer the opportunity to remember the sinking of HMS Vanguard and the terrible loss of life in Scapa Flow on that July day 100 years ago.

"We are very pleased that descendants of men who served aboard the ship will take part in the commemorations.

"There will be limited space aboard the vessels involved in the laying of wreaths above the wreck and so priority will be given to relatives who have travelled to Orkney for the occasion.

"Many other people from our community will want to play their part in commemorating the loss of the Vanguard and her crew and all are welcome at the services at Lyness Cemetery and back in the cathedral on July 9."