Two men who set up a hi-tech company in their garden shed could be worth up to £40m each when their internet firm floats on the stock market.

Kevin Grumball, 43, and his former lodger, Chris Barling, 44, started Actinic four years ago with £80,000 in a hut used to rear poultry on land at their home near Stratford-upon-Avon, in Warwickshire.

Their company is to be listed on the stock market with a value of more than £250m.

Mr Grumball and Mr Barling each have a 25% stake, but new share issues will push their stake down to 17%, leaving them a share value of about £40m each.

Actinic employs 40 people and provides website services, selling CDs that allow small businesses to set up their own e-commerce websites and credit check customers.

Its 5,000 customers range from one-man businesses to bigger organisations, including the London Symphony Orchestra, Hasbro, the Royal Opera House and Fulham Football Club.

Last year the company began operations in the US.