The business owners praised the party’s economic plans and said that, “this Conservative-led government has been genuinely committed to making sure Britain is open for business”. The letter pointed to particular actions taken by the government including, “tackling the deficit, helping to keep interest rates low and inflation down”.

While the parties have vied for the attention of small businesses – including appearances at the FSB’s policy conference in March – this letter said that those who had signed it in support felt the current government was taking steps in the right direction.

“We’ve been helped by their steps to lower taxes, reduce red tape, simplify employment law and get the banks lending,” the business owners explained, and also warned that a change would not just be risky, but “undo all the good work of the last five years”.

The range of businesses whose representatives signed the letter were from across the UK, with signatures spanning Scotland, Yorkshire, London, the South East and the West Midlands.

The news coincides with Cameron’s pledges to treble startup loans and invest in broadband, in his small business manifesto. The prime minister said that the Conservatives were the party of the “grafters and the roofers and the retailers and the plumbers”, and wants to see 600,000 new businesses started every year by 2020.

Read more on the lead up to the general election:

• Chuka Umunna: “We have to stop gold plating European rules and regulations“
• Lack of consensus on making spending cuts after election could lead to future tax rises
• General election 2015: A summary of party policies for UK business leaders

Official figures state that there were 346,485 business starts in 2013, and the Conservatives said there are now 760,000 more businesses than there were in 2010.

Shadow business secretary Chuka Umunna has said the government had overseen an increase in business rates of around £1,500 and Labour would cut, then freeze, the rates. Umunna previously told Real Business that Labour was looking to “champion all businesses, not just small businesses”, but that with constrained finances, the party thought it was most sensible to help 1.5m businesses with rate cuts.

“Ultimately, the relationship between larger and small businesses is symbiotic. Large businesses will rely on small business to provide a really important supply chain and small businesses rely on the larger businesses to provide custom,” Umunna added. He said that Labour wanted to help all of these businesses expand and grow. “Why? The clue is in the name – we’re the Labour party, and they’re the ones who create the jobs that we want to see – good, secure, better-paid jobs.”

The Conservatives encouraged firms to sign the letter via its party website and some 5,025 business owners responded. “We would like to see David Cameron and George Osborne given the chance to finish what they have started,” the letter said.

By Rebecca Smith