The number of self-employed workers has risen by 367,000 since 2008, the start of the economic downturn, according to figures from the Office for National Statistics (ONS).
The number of people who work for themselves now represents more than 14% of the UK's 30 million-strong workforce.
Figures released today by the ONS shows that 60% of the increase since 2008 occurred between 2011 and 2012, and eight in 10 of the new self-employed are aged 50 and above.
The ONS also said those who work for themselves on average work two hours more a week than those employed by somebody else, and are more likely to be male.
Taxi drivers, carpenters and joiners and farmers are four of the most common self-employed trades, with London clocking up the highest percentage, and the North East, the lowest.
Phillip Venn, commercial director at chartered accountants Boox, says the increase was unsurprising as much work is now project based.
"We expect to see a continued increase in self-employment throughout 2013 and the challenge is to ensure that these individuals understand their tax liabilities," he says.
While Xenios Thrasyvoulou, founder of online freelance marketplace PeoplePerHour, says the number of self-employed registering on its site had more than doubled in the past 12 months. He says the site had seen an 88% increase in people aged 55 and over registering.
The news comes as YouGov today announced that one in five employees believe redundancy is "somewhat or very likely" - one in six earning more than £50,000 believe redundancy is likely within the next 12 months.
Stephen Harmston from YouGov says: "It looks as though the downbeat economic news of the past few months will set the pattern for consumer confidence throughout 2013."