An estimated 700,000 small businesses are using the social networking site Twitter with 6,000 more joining every day, according to a recent O2 survey.

Small and medium-sized businesses are looking to Twitter as a way to cut marketing costs and directly communicate with clients and potential clients.

The poll of 500 small firms found that 17% are already using Twitter, with 25% of these SMEs signing up to the social networking site in the last month.

Nearly a third of those surveyed said they had saved up to £1,000 since signing up and 16% claimed that they had been able to save up to £5,000.

"The increase in small businesses using converged devices such as smartphones combined with the simplicity of Twitter represents a fantastic opportunity to further raise their profiles and increase efficiency," said Simon Devonshire, head of small business marketing at O2.