EBAY started in business by helping enthusiasts to swap novelty toys. Now it has become the fastest-growing forum for start-ups in Britain.

The Sunday Times has learnt that more than 23,000 enterprises are trading through the online auction site, with an estimated three-quarters of them using it as the sole way of conducting their business.

Ebay’s rocketing popularity has mirrored the rapid rise of online shopping in Britain — last year it grew from £13.5 billion to £40 billion. Last month Ebay’s British site had 8.7m sole users, making it the biggest overseas market for the American company.

The site’s attractions — virtually no set-up costs, little red tape and minimal overheads — have made it an ideal forum for start-ups. And Ebay has moved quickly to establish a sellers’ support network in order to sustain the growth in new businesses.

Wilmamae Ward, 36, is typical of the new breed of Ebay entrepreneur. The former public-relations executive began using the site to satisfy her tastes in vintage and designer clothes.

“After one particular buying spree I realised I had more clothes than I could wear in a lifetime so I started selling them,” she said.

Last June, three months after her first sale, she opened her own Ebay shop, The Gathering Goddess, went full-time and now turns over about £5,000 a month.

“As you build up your business, you realise there is a science to Ebaying,” said Ward. “It’s all about the key words you use to sell a particular item. You have 88 characters and you soon learn which words work and which don’t.”

As a registered Ebay “power seller”, Ward gets online support and a telephone helpline. There is also a power-seller conference — the first being held in London in the summer — as part of Ebay’s ambition to build a community of sellers.

The company allocates different levels of support depending on a business’s monthly turnover. These rise from bronze for companies earning more than £1,500 a month to titanium for businesses in the top tier. These must earn more than £95,000 a month and are given their own personal Ebay account managers.

Ebay refuses to disclose how many businesses are in this category. However, more than 10,000 traders are registered as power sellers, while the other 13,000 or so choose to trade without Ebay’s support.

Elspeth Knight, the company’s senior channel manager, said: “The beauty of the power-seller programme is that because shoppers are able to rate the traders they use, customer support becomes self- fulfilling. If they don’t offer good service, people don’t use them. It’s as simple as that.”

This self-policing principle is highly attractive to traders. The company claims only 0.01% of transactions involve non-delivery of goods or non-payment.