A study by Experian found that the average late payment for all UK firms increased in the third quarter of 2011 to 26.13 days, an increase of almost a day.

Although companies with one or two employees only saw an increase of half a day, the smallest rise, other small businesses faired far worse.

Those with between three and five employees saw average payments beyond agreed terms increase by more than a day to 23.01 days, only medium-sized firms and large businesses in the 51–100, 101–500 and 500-plus employee categories faired worse. Meanwhile, firms with 6–10 staff experienced an average increase of slightly less than one day.

The Forum of Private Business (FPB), Wanobe.com and The Business Woman’s Network have joined forces to campaign for a "micro business day", dedicated to recognising the importance of UK firms with ten or fewer employees.

Jane Bennett, head of campaigns at the FPB, said: "The jobs that will drive economic growth are expected to be created in micro businesses so it is important that we place the political spotlight squarely on them and make sure it stays there.

"That is why we are calling for a micro business day to highlight the crucial role played by the UK’s smaller businesses," said at the Forum, which provides the secretariat to the All-party Parliamentary Micro Business Group.   

"It is time for the Government to stop talking micro and thinking macro and instead focus on the real issues of the smallest businesses.

"Late payment is a huge issue, particularly for small businesses. While it is pleasing that the smallest micro businesses seem to be leading the way in minimising the problem, others are less able to do so - perhaps because employment law bureaucracy means they simply have less time to chase outstanding payments."