British markets spooked by poll showing Scots may vote to break up UK

British financial markets tumbled on Monday after an opinion poll showed for the first time this year that Scots may vote for independence next week in a referendum that could herald the break up of the United Kingdom.

The survey prompted concern bordering on panic among Britain's ruling elite, with Prime Minister David Cameron's Conservative-led government promising proposals this week to grant Scotland greater autonomy if it stays.

Cameron's job would be on the line if Scots vote on September 18 to secede, less than eight months before a national election planned for May. His spokesman said on Monday the government was not making contingency plans for the possibility of Scottish independence.

Sterling fell more than one per cent - its biggest one-day drop in 13 months - to $1.6141, long-dated government bonds tumbled and £3.7 billion ($6 billion) was wiped off the market value of five London-listed companies with large exposure to Scotland.

"Markets don't like uncertainty," said Alistair Darling, a former finance minister who leads the unionist 'Better Together' campaign, told reporters in Edinburgh. "For as long as there's uncertainty, you will get a bit of jitteriness in the system."

After months of polls showing nationalists heading for defeat, the survey by the respected YouGov pollster raised the real prospect that secessionists could achieve their goal of breaking the 307-year-old union with England.

If Scots voted to leave the United Kingdom, Cameron would face calls to quit before the general election, while the opposition Labour party's chances of gaining a majority could be scuppered if it lost its 40 Scottish lawmakers.

Cameron, who visited Queen Elizabeth in Scotland on Sunday, has insisted he will not resign. British media quoted a palace source as saying the monarch was concerned and had asked for daily updates on the situation.

A vote for independence by Scotland's 4 million voters would be followed by negotiations with London on what to do about the pound, the $2.1-trillion national debt, North Sea oil and the future of Britain's nuclear submarine base in Scotland ahead of independence pencilled in for March 24, 2016.

Better together?
With less than two weeks to go before the September 18 vote, the poll put the "Yes" to independence campaign on 51 per cent against "no" camp on 49 per cent, excluding undecided voters, overturning a 22-point lead for the unionist campaign in just a month, the Sunday Times said.

Less than 12 hours after the poll was released, Britain's second most powerful man promised on national television that plans would be set out to give Scotland more autonomy on tax, spending and welfare if Scots vote against independence.

"You will see in the next few days a plan of action to give more powers to Scotland," Finance Minister George Osborne said.