One in five start ups launch while owners are still in employment with another job, states a new survey from telephone answering service alldayPA.
A survey of 500 small businesses found 21 per cent of start-ups launched in the last 12 months began this way.
The study revealed the most common double job entrepreneurs are men between 25 and 34 years old.
The typical sectors where people launch businesses are Digital Services (18 per cent of double job start-ups), PR and Marketing (12 per cent), Design (11 per cent) and HR (5 per cent).
HMRC reports 1.2m UK workers have official second jobs, up from 1.05m in 2007.
Of these, 450,000 are self-employed second jobbers running their own business on the side, an increase of 40 per cent from 2006.
“This is a trend the government should be reacting to by cutting red tape for second job start-ups and simplifying the tax structure to help balance PAYE with self-employment and dividend payments," said Reuben Singh, chief executive officer at alldayPA.
“Such businesses may start small, but they be major sources of employment and income for years to come.”