A series of previously unknown sites set up to defend Scotland from attack during the First World War have been revealed

An audit by Historic Scotland to identify war-time heritage in the lead up to the centenary of the war later this year identified 900 buildings and places that were used for training or defence during the war, more than three times the number expected at the outset of the audit.

Plans to protect Edinburgh from any potential invasion were particularly extensive. War Office maps that were found in the audit showed a network of trenches and strongpoints at Portobello that stretched from the shore of the River Forth to the south of the city to prevent a land attack.

Among the records that have been added to or updated in the audit are 239 hospitals ranging from village halls to existing medical centres, 39 prisoner of war camps in Hawick, Edinburgh Castle and the island of Raasay, and 350 drill halls established to train volunteer soldiers.

Historic Scotland and the Royal Commission on the Ancient and Historical Monuments of Scotland (RCAHMS) will designate some of the remaining sites to recognise and protect their significance during the centenary of the First World War.

The audit's author, Dr Gordon Barclay said: "The audit has more than tripled the number of places known to be associated with Scotland's contribution to the First World War, both military and civilian, and has revealed an extraordinary variety of structures, reflecting Scotland's importance to the war effort.

"The audit is only the first step, and other places no doubt remain to be identified, and the war-time role of many other places will certainly come to light during the centenary of the war."

Culture Secretary Fiona Hyslop welcomed the findings.

She said: "Our World War One built heritage is a vital part of our historic environment and is key to educating us about Scotland's role in the conflict.

"As we prepare to commemorate 100 years since the start of the war, I hope people will use this research to learn more about this important period and contribute any information they have so we continue to piece together a fuller picture of Scotland's role.

"I also welcome the fact that Historic Scotland will recognise the significance of some of these assets through designation, helping to ensure they are safeguarded for future generations."

Allan Kilpatrick, of RCAHMS, said: "Scotland was on the front line during WWI. St Kilda was bombarded by a German U-boat and Edinburgh was bombed by a Zeppelin.

"The naval bases on the Forth, Cromarty and Scapa Flow were essential to protect Britain's navy and her shipping. Large parts of the landscape were transformed by structures designed to repel any invasion or attack, and it is remarkable just how many WWI remains can be still be seen today.

"Having these records online and in one place, provides a perfect starting point for further study."

All of the records, which feature hundreds of modern and historical photographs of sites, are available to view online at www.rcahms.gov.uk/firstworldwar