Standard Life has sparked a fresh row in the debate over Scotland's future as the finance firm revealed it could move some of its operations if the country votes for independence.
The pensions and savings company - which has been based in Scotland for 189 years - said it would ''take whatever action we consider necessary'' to give continuity to its customers.
Unionist politicians said the actions of the Edinburgh-based firm showed leaving the UK would be a ''disaster for Scottish jobs''.
But Scottish First Minister Alex Salmond insisted an independent Scotland would be a ''more competitive place to do business''.
The row erupted after Standard Life's annual report revealed it had begun to set up additional registered companies outside of Scotland to transfer part of its operations to "if it was necessary to do so''.
Chief executive David Nish said this had been done amid continued uncertainty ahead of the Scottish independence referendum, with doubts remaining over a ''number of material issues'', including the currency of an independent Scotland and the financial regulatory regime.
The move by Standard Life comes after Chancellor George Osborne and his Labour and Liberal Democrat counterparts all ruled out entering into a formal currency union with an independent Scotland - the Scottish Government's preferred option, which would allow the country to continue to use the pound if it left the UK.
Mr Nish stressed work to establish the new registered companies was a ''precautionary measure to ensure continuity of our businesses' competitive position and to protect the interests of our stakeholders'' .
At the same time, the Royal Bank of Scotland warned a vote in for independence in September's referendum could impact on its business.
It said: ''The group's borrowing costs and its access to the debt capital markets and other sources of liquidity depend significantly on its and the UK Government's credit ratings, which would be likely to be negatively impacted by political events, such as an affirmative outcome of the referendum for the independence of Scotland.''
Chief Secretary to the Treasury Danny Alexander said the positions of Standard Life and RBS showed ''the risks of independence becoming ever clearer''.
The UK government minister said: ''It's common-sense that when you have something that works there will be adverse consequences if you rip it apart."
Similarly, Business Secretary Vince Cable said Standard Life was "one of a series of Scottish finance companies giving warnings".
He added: "Businesses are now coming out publicly to say they're worried about the referendum.
"It's clear they're not doing this for political reasons.
"They're talking about real jobs and the future of the Scottish financial sector and people in Scotland will take note of this."
But Mr Salmond insisted: "Standard Life will find Scotland a good place to do business - as it indeed does business in 10 countries around the world."
He said there was "substantial evidence" that "an independent Scotland will be a more competitive place to do business".
The Scottish Government has put forward the "concept of a shared currency and regulatory framework" for after independence, Mr Salmond said, adding this was "exactly the sort of things Standard Life have been calling for''.
The First Minister had been challenged on the issue at Holyrood by Scottish Labour leader Johann Lamont , who warned: "If Scotland leaves the United Kingdom, people's jobs will leave Scotland."
She demanded: "'How many more companies need to leave Scotland before the First Minister admits a Yes vote would be a disaster for Scottish jobs?''
Fellow Labour politician Alistair Darling, the former chancellor and leader of the pro-UK Better Together campaign, claimed Mr Salmond's ''obsession'' with independence was putting thousands of jobs at risk.
The Edinburgh South West MP said: ''Independence will cost jobs.
"This is the reality of Scotland leaving the UK and losing the UK pound.
"Companies like Standard Life rely on the strength, security and stability of the UK."
Scottish Tory leader Ruth Davidson said Standard Life's 5,000 workers north of the border would now be "wondering whether separation could see them having to move south to keep their job".
She stated: "When one of Scotland's most prominent financial institutions warns it may move its operations out of Scotland in the event of independence, it's time to sit up and take notice."
But Scottish Finance Secretary John Swinney said he looked forward to Standard Life playing a part in building a "strong Scottish economy in the future''.
He said: ''When Standard Life previously expressed concerns about the consequences of devolution, these concerns ultimately proved to be unfounded and the company has successfully continued to grow its business here, underlined by the announcement just this month of a £75 million acquisition in central Edinburgh described as a 'long-term investment'.
''Standard Life's strengths lie in its workforce here in Scotland. We are very happy to engage with the company to address the issues raised in their annual report and we look forward to the company continuing to play its part in building that strong Scottish economy in the future."
Mr Swinney continued: "Standard Life's comments show exactly why our proposals for a formal currency area are the right proposals, why they are in the best interests of business on both sides of the border and why that is what will be implemented by both governments.''
Similarly, Blair Jenkins, chief executive of the pro-independence campaign Yes Scotland, said: ''Standard Life wants to see agreements on currency, regulation and taxation, which is exactly what the Scottish Government has proposed.
''Standard Life wants a formal currency union and so do we. The only threat to that comes from the refusal of the No campaign and the UK Government to get involved in sensible discussions."
Liz Cameron, chief executive of Scottish Chambers of Commerce, said that businesses "plan best in a stable economic environment" and added that the referendum was "necessarily creating some degree of uncertainty".
She said: "Whether Scotland chooses to vote Yes or No, they will need stronger detail from both sides of the campaign on issues such as tax, currency and European Union membership in order that they can best plan for the future.''