By Jonathan Davies

Representatives of as many as 5,000 small businesses called for the Conservatives to be "given the chance to finish what they started", in a letter printed by the Daily Telegraph.

The letter, the businesses say the coalition government kept the UK "open for business".

However, the credibility of the letter has come into question after it emerged that it was sent from a CCHQ (Conservative Club Headquarters) address. The letter started life as an online petition headed by Tory peer Karren Brady.

It reads: "We've been helped by their steps to lower taxes, reduce red tape, simplify employment law and get the banks lending.

"We would like to see David Cameron and George Osborne given the chance to finish what they have started."

David Cameron has pledged to treble start-up loans and boost broadband investment. And in a speech in north London today (Monday), the Prime Minister will say that a Conservative government will aim to help create 600,000 new small businesses each year by 2020.

"We know it's the people who take risks, start out on their own, wake up at the crack of dawn to open up their shop and do their books on the kitchen table at midnight who create jobs," he said.

"We are the party of the grafters and the roofers and the retailers and the plumbers. We get them, we respect them, we understand them, we back them."

Chuka Umunna, Labour's shadow business secretary, said: "The Tories have spent five years letting down Britain's small businesses. Government scheme after government scheme designed to boost finance for small firms has failed, and small business lending has fallen by £500m in the last three months.

"With Labour, the tax burden on small firms will be lower than under the Tories," he said.