LONDON A former secretary general of NATO has warned that Scottish independence would be "cataclysmic" because breaking up Britain would rob the West of a major anchor of stability and solidarity at a difficult time.
George Robertson, a former British defense minister and NATO head from 1999 to 2003, said a vote for independence at a September 18 referendum would erode Britain's role in the West and undermine the global balance of power.
Robertson, a Scot, said Scotland ending its 307-year tie with England would have consequences across Europe, triggering a possible fragmentation as breakaway movements in Catalonia and the Basque country in Spain and in Belgium followed suit.
"The loudest cheers for the break-up of Britain would be from our adversaries and from our enemies," Robertson said in a speech delivered at the Washington-based U.S. think tank, the Brookings Institution, late on Monday. An audio recording of the speech was made available on the think tank's website.
"For the second military power in the West to shatter this year would be cataclysmic in geopolitical terms ... Nobody should underestimate the effect all of that would have on existing global balances and the forces of darkness would simply love it."
He said splitting up the United Kingdom, Washington's staunchest ally on the global stage, would lead to a torrid, complex divorce that would take years and deprive the West of a serious partner at a time "when solidity and cool nerves will be vital" amid renewed territorial intimidation.
He warned the Scottish National Party's (SNP) promise to get rid of Britain's Trident nuclear submarine fleet from western Scotland would also have wider implications.
"It is one thing to unilaterally disarm yourself but to unilaterally disarm your neighbor is playing with fire," Robertson said. "The ripple effects will go much wider than our own shores."
Arguing this was not a purely domestic matter, Robertson urged the U.S. government and other UK allies to make their views public as Scottish independence would affect them too by undermining stability in the region.
Robertson's comments came as Scottish First Minister Alex Salmond was in New York on a trade mission.
The Scottish government dismissed Robertson's comments as "crass and offensive" and that he added nothing positive to the debate.
Opinion polls have narrowed this year although the nationalists continue to trail in support, with the economy and future currency emerging as major battlegrounds in the discussion.
British economic research group, the National Institute of Economic and Social Research (NIESR), said on Tuesday it would not be in the interests of Scotland nor the rest of the United Kingdom to share the pound after independence.
This contradicts the SNP's view that both countries would save on currency conversion costs if Scotland kept sterling, a proposal flatly rejected by the main UK parties. NIESR said the cost of a potential currency crisis if a sterling union broke up would dwarf other savings.
NIESR also said Scottish independence might ring alarm bells when ratings agencies looked at the rest of the UK's general government debt as a share of GDP. This is likely rise above 100 percent due to the Westminster government's commitment to honor all UK debts, and seek separate recompense from Scotland.
(Reporting by Belinda Goldsmith and David Milliken; Editing by Raissa Kasolowsky)