It is compelling because it is so simple. You pitch a business idea to a panel of investors and receive feed-back and a cash offer or rejection within minutes.

Dragons’ Den, the hit BBC series, has inspired thousands of would-be entrepreneurs to consider quitting work to start out on their own. But how can they secure help and capital outside the television studio?

James Caan, the newest and “nicest” dragon, says that the key to real-world success for start-ups is to talk to as many people as possible and to chase all potential sources of funding. “Do whatever you have to. Hit angels, banks, friends and family. You do not know who will bite.”

He adds that a comprehensive business plan is essential. This can be drawn up with free help from bodies listed at BusinessLink.gov.uk (see box, facing page), but should be checked by an accountant – a quick job that may be offered without charge in the hope of future custom.

A credible plan depends on market research. Mr Caan says that this is where many of the proposals sent to his website (www.jamescaan.sites.subhub.com ) fall down. “You need to ask people whether they would buy the product, and check how the competition is doing,” he says.

The deals in Dragons’ Den, which tend to start at £50,000, are the smallest that Mr Caan considers. But a growing number of business angels are looking to invest as little as £10,000 in high-growth ventures. Most angels are enthusiasts who bring their own skills, experience and contacts to the table – as well as cash – in much the same way as the BBC’s dragons. They can be approached through networks listed at the website of the British Business Angels’ Association at bbaa.org.uk.

One low-cost service is Angels Den (angelsden.co.uk), which allows candidates to post a business summary on a secure online database for £99. If any of the 2,000-plus angels with access to the summaries express interest, the applicant can then post a detailed business plan for £400.

Bill Morrow, of Angels Den, says that 17 per cent of customers have found funding to date. He adds that applicants whose summaries are “too technical” or “academic” are often rejected, as are those who make spelling mistakes.

Two users who pitched it right are Colin Allison and Mark Bedworth, of PINoptic, who recently sold a 30 per cent stake in their fledgeling business to a team of five experienced angels after two telephone calls and a meeting. The pair had spent months seeking finance for their design for a safer variant on chip-and-PIN systems and say that Angels Den was a “godsend”.

Mr Allison says that PINoptic will work closely with the new angels, one of whom is set to attend board meetings as investor-director. Mr Allison is happy to lose a significant chunk of the business for the chance to take it forward. “It is better to have 20 per cent of something big, than all of nothing,” he says.

Another inventor who is prepared to concede equity is not sold on angels, however. Mark Collins was tempted to use them to finance development of Slip Guardian – a device that measures the slipperiness of surfaces – but the chemical engineer says that too many are in it for “egos”.

Instead, he took his idea to Trevor Baylis Brands (TBB), a service founded by the inventor of the clockwork radio. For £149, TBB evaluates whether an idea is original and has a market. If it is viable, staff work to patent or protect the product, develop it and get it to the manufacturing stage, forming a new company around it or securing a licensing agreement with an established player. In return for this help, TBB takes a 33 per cent stake.

Lynn Miller, of TBB, says that inventors can decide how much input they have, leaving the service open to those who have a good idea but no time to develop it. This does not apply to Mr Collins, who devotes a day or two a week to the project. His commitment is set to pay off – a blue chip company has offered £4 million for the gadget.

Mr Collins says that without help from outside, he would have had to pay between £100,000 and £200,000 on development over two years.

Start-up expenses for a service company can be much smaller. Emily Bendell launched her lingerie and party-plan business, Blue Bella, in 2005. The recent Oxford graduate started small, moving from London to her father’s home in Nottingham to cut nonessential spending. Initially, she spent £550 printing catalogues and £1,000 on stock – costs met with savings and family help.

Ms Bendell, 26, who now employs three and leads a team of 60 self-employed consultants, took advantage of free help from a number of sources. Before starting out, she took advice from the Portobello Business Centre in London. Later she accepted friends’ offers to design her catalogue and build the website www.blue-bella.com. She started with total commitment and no fallback option. “It helped me to focus, but you have to do your homework,” she says.

The nuts and bolts of building a business

- By telling people about an idea, you put it in the public domain, leaving others free to copy it. It can be safeguarded, however, using patents, trademarks, copyright and domain names. BusinessLink.gov.uk has articles on the subject and contact details for small business services that offer free and confidential face-to-face advice.

- It is essential to establish whether a product or service has what James Caan calls “market acceptability”. By this he means that people who have seen a demonstration say that they would pay for it. Other important market research includes looking at how similar ventures are performing.

- Research is a crucial part of your business plan, which should project a return. This can be drawn up with free help from Business Link advisers. Palo Alto’s Business Plan Pro software can help users to prepare a smart document, but it should be used along with advice.

- Help from Business Link advisers is an invaluable first stop. However, business consultants, accountants and lawyers can dedicate more time and expertise to your business for a fee. These can be located through Business Link and the Law Society website at lawsociety.org.uk. A sympathetic bank manager is another must-have for most entrepreneurs.

- Funding can be a struggle. Check whether you qualify for grants or subsidies at the Business Link website’s grants and support directory before raiding savings or taking on debt. Extra help is available for disabled people, who qualify for mentoring through the Ready to Start scheme from Leonard Cheshire and Barclays. Advisers can talk you through standard funding options, from bank loans to angels. Most venture capitalists seek businesses with a track record and market value in the millions of pounds, rather than start-ups.