British Prime Minister David Cameron heads to Scotland today to make the business case for it remaining part of Britain as 200 business leaders signed an open letter backing independence.
Questions over whether Scotland's economy could go it alone have been at the heart of the campaign -- with a rival group of 130 captains of industry claiming yesterday that independence would be "bad for business".
Scotland votes in three weeks' time on whether to become a separate country after over 300 years of union with the rest of the United Kingdom.
Most opinion polls currently suggest the proposal is set to be rejected.
The "Yes" and "No" camps have traded statistics and accusations on everything from whether Scotland could keep using the pound to what share of Britain's national debt it should take on if it broke away.
Cameron is set to urge Scots not to turn their backs on "one of the oldest and most successful single markets in the world" in a keynote speech to CBI Scotland, a leading business lobby group, in Glasgow.
He will say that Scotland does twice as much trade with the rest of the United Kingdom as with the rest of the world put together, according to pre-released extracts of his speech.
He is also expected to highlight "the opportunities that come from being part of something bigger".
Cameron has been keeping a low profile on the campaign trail due to his centre-right Conservative Party's unpopularity north of the border, where it only holds one out of 59 House of Commons seats.
As the prime minister was set to arrive in Glasgow, The Herald newspaper published a letter from 200 business people arguing that an independent Scotland would be better for business.
This is because policy would be set by people "who truly understand and care most" about Scotland, not politicians in London, according to the letter.
It added that independence would provide "more opportunities for our talented and determined young people to stay and succeed".
The signatories range from big business leaders such as Brian Souter -- chairman of major transport group Stagecoach and a prominent donor to the independence campaign -- to the owners of smaller enterprises such as guest house owners.
The letter comes the day after over 130 captains of industry, including top executives at HSBC bank and mining group BHP Billiton, signed another open letter in The Scotsman newspaper saying "the business case for independence has not been made".
