These fall into three categories: those set up mainly by women as second jobs in industries such as retail, catering and leisure; those that people tentatively set up while still in employment; and those, frequently described as "hidden", run by people who do not believe that they are in business, usually because they have turned a hobby, such as carpentry, into a money- making enterprise.
The number of such businesses has almost doubled, to more than 1 million, over the past eight years. As a result they account for more than a quarter of all small businesses in England and Wales.
David Lavarack, small business services director at Barclays Bank, says: "These figures reflect the changing nature of UK enterprise and employment. With the development of technology, greater flexibility of hours and working from home, people are now able to `dip their toes in the water' before fully committing themselves to running their business full-time."
However, there are still a lot of young people eager to try their hand at running their own businesses. The LiveWire Business Start-Up scheme, launched by Shell UK in 1982, aims to give a boost to such entrepreneurs and has begun its search for the 1997 award winners.
Prizes worth more than pounds 200,000, along with free business advice, are some of the benefits on offer to those between 16 and 25 entering the competition.
This year's winners, Garry Tibbitt and Michael Richford of Optimum Test Solutions, said receiving the award was the best business reference they could have wanted. Sandy Ogilvie, a director of LiveWire UK, said that everyone who takes part benefits because of the advice they get about producing a business plan. More than 70,000 young people have been helped in this way.
The competition is open to those between 16 and 25 who have started a business since 1 February 1996. Entries must be received by 31 January 1997. Ring 0345 573252 for information.