Alistair Darling and Charles Kennedy lined up for Scottish pro-union drive Alistair Darling, well-respected during his tenure as chancellor, could co-lead the campaign against Scottish independence. Alistair Darling, Charles Kennedy and the former Tory leader in Scotland, Annabel Goldie, are being lined up as the main faces of the pro-union campaign in the referendum on Scottish independence, sources in the three parties confirmed Wenesday night. As Labour and the Liberal Democrats expressed the hope that David Cameron would adopt a lower profile after a faltering start, the pro-union parties said they would place the future of the economy in an independent Scotland at the forefront of their campaign. Darling, who is widely respected in all parties after warning of the depth of the recession on the eve of the financial crash in 2008, will be the main voice in the pro-union's economy campaign, which will focus on the burden Scotland will face in assuming its share of the UK's £1.4tn debt in 2014. The former chancellor is also expected to point out that Alex Salmond, the SNP leader, endorsed the Royal Bank of Scotland move to take control of ABN AMRO in 2007. This led to the near collapse of the Edinburgh-based bank, which had to be bailed out by the UK taxpayer to the tune of £187bn, a sum that was more than the entire GDP of Scotland. The first minister of Scotland on Wednesday night moved to deflect the pro-union campaign's economic arguments when he said that an independent Scotland should not be liable for the RBS debts, on grounds that its problems were caused by failures of regulation by the UK Financial Services Authority. In an interview with Channel 4 News, Salmond said that an independent Scotland would demand 90% of the oil revenues from the North Sea, which were worth about £5.9bn a year. London is likely to argue, however, that oil revenues belong to the UK as a whole. An independent Scotland would be entitled to about 8% of the revenues, in line with its portion of the UK population. This would amount to about £545m, according to Channel 4 News. Salmond said: "The geographical share of North Sea oil - that in the Scottish continental shelf - would accrue to Scotland. What is in the English continental shelf would accrue to England. With a proper share of our resources Scotland would be the sixth most prosperous country in the developed world. About 90% of the revenue bearing oil and gas fields are in Scottish waters. Salmond said an independent Scotland would accept liability for about 8% of the UK debt. I am afraid we are going to have to bear our fair share of the Treasury incompetence. That would leave us with a lower debt per GDP than the UK has at the present moment. He was critical of the way Cameron was proposing to devolve to Holyrood powers to hold a referendum - with two strings attached. Those conditions are, a vote being held by a specific date, probably 2013, and only a simple "in or out" option to be posed. This is designed to prevent Salmond proposing the "devo max" question, in which voters would be asked if they wanted full-scale devolution, a move that would fall short of independence. The first minister, who said on Tuesday that he would stage a referendum on his terms in 2014, told Channel 4 News: "A consultative referendum is within the provenance of the [Scottish] parliament. What we object to is this extraordinary attempt by Downing Street for the prime minister and chancellor to start pulling the strings of the Scottish referendum. There is more control from London in a sort of Thatcher-esque manner. We think these days are over. Cameron and Osborne would be well advised to recognise the new reality, where Scotland votes democratically for something to be done. What is done is fashioned and made and decided by the people of Scotland not Tories in Downing Street. Salmond's tactics, whereby he is trying to portray the UK cabinet's announcement as a power grab by English Tories, have prompted Labour and Lib Dems to warn Downing Street that the Tories must adopt a lower profile. Ed Miliband endorsed Cameron's decision to press on with a quick poll in friendly exchanges in the Commons. But the Tories have been told that the pro-union campaign must be based in Scotland. Goldie is widely seen as the strongest Tory because she out-polls her party. After the leaders' debate in last year's Holyrood election campaign Goldie came second behind Salmond in a poll on who would make the best first minister. Darling is keen to play a role, particularly on the economy. But he does not want to dominate the pro-union campaign as he wants to avoid falling into a Salmond trap of making it presidential. Charles Kennedy is seen as an emollient figure who would perform well against Salmond. Sir Menzies Campbell, Kennedy's successor as Lib Dem leader, will also play a prominent role. The constitutional role of the UK's supreme court means any legal challenge to a Scottish referendum on independence is to be brought directly before judges in Westminster. Under the Scotland Act 1998, the law that established the Scottish parliament, issues raised by devolution were to be decided by the Judicial Committee of the Privy Council; that responsibility passed on to the supreme court when it was established in 2009. Such a question is to be heard by a panel of supreme court justices, composed of seven or nine of the country's senior judges. Of the court's 12 justices two are -traditionally Scottish lawyers with experience of the legal system north of the border: Lord Hope is deputy president of the supreme court and Lord Reed has yet to take up his seat. Both, it is expected, would participate in such a hearing. A challenge to a poll on independence could be brought by Scotland's lord advocate, who works for the devolved government in Holyrood, or the advocate general for Scotland who works for the Westminster government on its "reserved interests." Anyone with "an interest" may initiate an action in Scotland's court of session, which would transfer the case to the supreme court in Westminster for a full hearing. Many suspect the Scottish National party has attempted to undermine the authority of the court's justices. Owen Bowcott