Organisations representing thousands of firms in Scotland have raised concerns over the SNP's business-rates policy in a joint statement released a week before the Holyrood election.

Scottish Chambers of Commerce, Scottish Engineering, Scottish Tourism Alliance, Scottish Property Federation and the Scottish Retail Consortium fear companies in Scotland will continue paying higher rates than those south of the border under another SNP government.

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The main poundage rate has increased to 48.4p in the pound while the extra supplement levied on larger firms on top of this has doubled in Scotland from 1.3p in the pound to 2.6p.

South of the border, the supplement has remained at 1.3 pence in the pound.

The doubling of the supplement which came into effect this month is expected to add an extra £60 million each year to firms' rates bills and affect one in every eight commercial premises in Scotland, the organisations said.

They claim comments made by SNP leader Nicola Sturgeon at the launch of the party's manifesto suggest the increased charge will remain in place during the next Parliament.

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Liz Cameron, chief executive of Scottish Chambers of Commerce, said: "The decision to double the large business supplement puts many Scottish businesses at a competitive disadvantage to their counterparts in England at a time when the Scottish economy is underperforming that of the UK as a whole.

"This additional tax affects a wide range of businesses, including shops, offices, factories and hotels for whom an increase in their fixed costs is the last thing they need at the moment.

"This is another reason why the forthcoming review of business rates in Scotland must be fundamental and comprehensive."

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Scottish Conservative leader Ruth Davidson said: "Income from business rates alone has risen by 42% since the SNP came to power, meaning money which could be used to employ a new member of staff or take on an apprentice is going straight to John Swinney.

"The SNP simply cannot ignore these Scottish business groups - it is time to act.

"Wrecking Scotland's economy with unjustified tax rises will only chase businesses away, leaving us with less money to pay for schools and hospitals."

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File photo dated 16/10/15 of Deputy First Minister John Swinney who has written to George Osborne to urge him to abandon his plan to raise a budget surplus by the end of the decade, and move to a budget balance instea

SNP campaign director and Deputy First Minister John Swinney said: "The SNP has delivered for businesses across Scotland - our small business bonus has already saved firms around £1 billion in total so far, and if re-elected we will extend the scheme to lift 100,000 companies out of business rates altogether.

"We are also committed to reviewing the wider business rates system to make sure it supports economic growth and jobs creation - with an emphasis on ensuring Scotland remains the most competitive place in the UK to do business."