Among the signatories are 102-year-old British Army veteran, Jimmy Sinclair, who fought the Germans in North Africa, Lieutenant Commander Colin May, a former senior intelligence officer at the Faslane nuclear submarine base and Keith Brown, a Scottish Government Minister and former Royal Marines Commando who saw action in the Falklands war.

In an interview with the Telegraph newspaper, Dannatt said, "As an Englishman who is a quarter Welsh I fought alongside British Army colleagues, and buried too many, to ensure that the United Kingdom would remain the same today as it was yesterday, and we hoped would be the same tomorrow."

But the 18 veterans, from all three branches of the UK armed forces, who signed an open letter Monday responded furiously accusing the former head of the British army of using the sacrifice of their colleagues for "political advantage".

"How dare [Dannatt] take their sacrifice in vain and try to turn it to political advantage - particularly having presided over the destruction of Scotland's historic regiments," the joint letter reads, noting that people who serve in the armed forces and veterans hold different views on Scotland's future. "We are all voting Yes on Thursday, others will vote No," it said.

At the weekend former Labour Prime Minister Gordon Brown also drew comparisons to Britain's war time role in an effort to persuade voters to vote against Scottish independence.

"As we commemorate 1914 and the anniversary of the start of the First World War there is not a battlefield in Europe where Scots, English, Welsh and Irish people did not fight side-by-side for a common cause," Brown told an audience in the Scottish Borders.

During WWI British troops from Scotland suffered disproportionately higher losses than their counterparts from the rest of the UK, as 26.4 percent of Scots who fought during that conflict were killed in action, compared to 11.8 percent amongst troops from England. Only the Turks and Serbs suffered higher, per capita, causality rates than Scottish soldiers.