Investors in British financial assets breathed a sigh of relief on Friday, spared a prolonged and unprecedented degree of uncertainty from the United Kingdom splitting apart after Scotland voted against independence.

Stocks were called to open up by more than one percent, sterling rose to a two-year high against the euro, and currency market volatility - which had reached historically high levels ahead of Thursday's vote - quickly subsided.

Scotland's vote against independence ended a fraught two weeks for markets that had seen the value of sterling fall sharply after some polls suggested the 307-year old union was on the brink of collapse.

The bounce for sterling was much less pronounced than some analysts had forecast, with the currency falling back after its initial gains to be up just 0.3 per cent against the dollar.

But the vote not only keeps Britain intact but also reduces the likelihood of it leaving the European Union, potentially a much greater risk for markets and something Scottish independence might well have precipitated, analysts said.

"The 'no' vote removes the huge political and economic uncertainty of untangling the 307-year-old union. A large downside risk to UK growth has lifted," HSBC strategists said in a note on Friday.

London blue chip stock futures and spreadbetter calls pointed to a 1.2 percent rise when markets open later on Friday.

The cost of insuring against big swings in sterling over the next week more than halved to 5.675 per cent from a close on Thursday of 11.8 per cent. Volatility had risen to levels not seen since the collapse of Lehman Brothers in 2008 and the unusually uncertain UK general election of 2010.

Sterling itself, already pushed up on Thursday by speculation on markets that Alex Salmond's nationalists had fallen short of the majority needed for independence, rose to a two-year high against the euro, with the single currency trading as low as 78.10 pence.

It came back off its peak against the dollar above $1.65, but was still up a third of one percent on the day at $1.6460 .

"Markets can move on from this event now, but the fate of the pound is still subject to great debate," said Chris Weston, chief market strategist at IG in London.

UK Prime Minister David Cameron, said: "I've just spoken to Alex Salmond, congratulating him on a hard-fought campaign. I'm delighted the SNP will join talks on further devolution.

"Now it is time for our United Kingdom to come together and move forward.

"The debate has been settled for a generation ... there can be no disputes, no re-runs. We have heard the settled will of the Scottish people."

Scotland’s First Minister and nationalist leader Alex Salmond, said: "Scotland has by a majority decided not, at this stage, to become an independent country. I accept that verdict of the people and I call on all of Scotland to follow suit in accepting the democratic verdict of the people of Scotland."

On the promises by Britain's main political parties to devolve more powers to Scotland: "Scotland will expect these to be honoured in rapid course."

Alistair Darling, leader of the Anti-Independence Campaign and former Finance Minister, said: "We have chosen unity over division, and positive change rather than needless separation."

"Every political party must now listen to (the public's) cry for change which could be echoed in every part of our United Kingdom but had the opportunity to express itself first in Scotland." - Reuters