Clickmango, the natural health website fronted by actress Joanna Lumley, said yesterday that 11th-hour attempts to find a backer willing to keep the business going had failed.

The closure of what had been one of the more high profile internet operations will deepen the gloom surrounding the business-to-consumer online sector. The firm is understood to have been holding discussions in the past few weeks with a number of potential investors including one of the four big supermarket chains but was unable to agree a deal.

Clickmango was founded a year ago and became a metaphor for the mania which swept the internet business last summer. Founders Robert Norton, a former Reuters journalist, and Toby Rowland, son of the late tycoon Tiny Rowland, famously raised £3m in just eight days after their first City presentation.

Mr Norton yesterday maintained that he was still a "fierce believer" in the internet as a medium for commerce and said Clickmango had been the victim of poor timing.

"The perceived exit opportunities for investors in e-tailers are definitely down on what they were a year ago and that makes it very difficult in the fundraising market. It is very sad. We were ahead of all our targets but we've been unlucky with our timing and there has to come a point where you draw a line and say you've come as far as you can."

The two were at pains to stress that they had taken the decision to close while still able to pay staff and creditors rather than allowing the business to collapse. "The Boo fiasco did no one any good and it's important that we are doing this in an orderly manner," Mr Norton said. "There will be no staff wandering out with computers."

Clickmango announced its intention to close at the beginning of August but said a week later that negotiations were taking place which might lead to the rescue of the business. The site will now be taken offline on Tuesday and its office, which was staffed by 18 people, will close at the end of the month.

Atlas Venture, which last September provided the bulk of the £3m start-up cash, was unwilling to provide further funds. Boo.com was by far the most high-profile dot.com failure so far when it collapsed after eating up a reported £80m of funding.