Alex Salmond claimed a victory yesterday as the Treasury pledged, in the event of a Scottish vote to leave the union, to honour all UK government debt issued up to the date of Scottish independence.
Mr Salmond said the pledge had strengthened the bargaining hand of a future government north of the border.
"We remain prepared to negotiate taking responsibility for financing a fair share of the debts of the UK provided, of course, Scotland secures a fair share of the assets," the Scottish First Minister said, adding that the Treasury's announcement "makes clear that Scotland would be in an extremely strong negotiating position to secure that fair deal".
In order to reassure investors in Gilts ahead of the referendum on Scottish independence in September, and to avert the possibility of a damaging spike in market interest rates, the Treasury has promised to stand behind Britain's entire £1.3trn national debt.
The Treasury will continue to pay off all the claims, even after a "yes" vote in the poll. Negotiations over how much an independent Scotland would owe the rest of UK would take place following a vote, and the new Edinburgh government would be a debtor to London. An alternative approach, but one rejected as too risky, would have been an attempt to divide the existing debt stock between a newly independent Scotland and the remaining UK.
Despite Mr Salmond trying to generate political capital from the Treasury's announcement, it was described as a "sensible move" yesterday by the former Chancellor Alistair Darling, who leads the pro-union Better Together campaign. The Treasury also denied that the move benefited Mr Salmond's negotiating position on the future division of the UK's liabilities.
Mr Salmond has said that any trepidation in the bond markets over the safety of Gilts is a result of London's refusal to discuss the terms of independence before next autumn's ballot. The "yes" campaign is presently trailing in opinion polls, although the Secretary of State for Scotland, Alistair Carmichael, has warned against complacency over the September vote.
The Treasury said: "In the event of Scottish independence from the United Kingdom, the continuing UK government would in all circumstances honour the contractual terms of the debt issued by the UK government."
By 2016/17, when Scotland would be expected to secede, the UK's national debt is projected to hit £1.6trn.
Other economic matters to be negotiated in the event of a "yes" vote include whether Scotland will use Sterling. Mr Salmond said sharing a currency post-independence would be "common sense" but there would be complex negotiations about whether Scotland would be represented on the Bank of England.
Gilts by numbers
£1.3trn UK national debt today.
£1.6trn Projected debt in 2016/17 when Scotland could depart.