If booming levels of self-employment are an indicator of a thriving economy, then Greece is the powerhouse of Europe. Just under a third of the population of this austerity-ravaged nation are self-employed, more than double the EU average. Spain is another go-getters’ paradise, it seems: with half an entire generation out of work, self-employment among the young has surged. And then there’s Britain, where around 40% of the rise in jobs since 2010 is down to self-employment. If our rulers are to be believed, here is entrepreneurial flair and British dynamism in action, a vindication of the government’s “long-term economic plan”. But the plight of the self-employed is being ignored. It is time that the left began championing their cause.

Independence, flexibility, “being my own boss”: this is how many self-employed people positively appraise their situation. In a country where power in the workplace has shifted so decisively towards employers – benevolent or tyrannical, it’s the luck of the draw – you can see why self-employment is almost a refuge for many. But self-employment spells precariousness, insecurity and falling living standards for all too many. Last week George Osborne lauded figures indicating that wages were rising; but what is often neglected is that the 15% of British workers who are self-employed are stripped out of these figures. There is little up-to-date research on their income, but the Resolution Foundation suggests that between 2006-07 and 2011-12 their weekly earnings dipped by a staggering 20% – and there was a big rise in underemployment, or self-employed people doing far fewer hours than they would like.

“Look at the new businesses being created under our watch!” proclaim the Tories, hailing booming levels of self-employment as an exercise in job creation. But only 17% of self-employed people in this country have any employees at all, lower than anywhere else in Europe. Self-employment is often a means for businesses to hire workers without offering the rights and responsibilities that normally come with employment: private pensions, paid holidays, sick pay or maternity leave, for example.

According to the Royal Society of Arts, only 11% of self-employed people believe the welfare state is fair for people like them. “A self-employed builder has no recourse to statutory sick pay should they have an injury on site,” its report, Boosting the Living Standards of the Self-Employed, points out; and “a self-employed cleaner would have no access to statutory maternity pay were they to become pregnant”. As one self-employed academic and writer put it to me: “Getting a mortgage, impossible; renting a flat, very difficult; you get ill, you lose money; you go on holidays, you lose money; you run out of work, getting benefits is a lot harder than when you get fired from a job.”

A sign-language interpreter tells me that many work for less than the minimum wage after costs are taken into account. “The most difficult part is chasing up unpaid invoices,” says a make-up artist in the Lake District, voicing a common complaint. A data inputter similarly has to wait weeks for a school academy federation to cough up, and resents the lack of social security. “If the government expects a significant proportion of the working population to be self-employed it needs to provide a safety net.”

Then there’s the phenomenon of what could be called “self-unemployment”, a convenient means of massaging the employment figures. One former delivery driver told me he became self-employed to escape the “usual silly sanctions” imposed by jobcentres, but ended up making a loss.And take a graphic designer forced into self-employment after the collapse of Lehman Brothers. Though officially self-employed, “work is so hard to come by and competition so fierce, I earn a negligible amount”, he says, and is eating through the remainder of his savings.

“Skiver” and “scrounger” bashing has had very real consequences. “A generation ago, such low incomes would have seen us heading straight to the jobcentre,” he says. “Now the stigma of unemployment is so fierce and the hoops so difficult to jump through, people like me prefer to register as self-employed.” The Tories would say he’s a go-getter. “I’m a single bit of paperwork away from being the focus of all their bile,” he says.

It’s up to the left to champion the rights of the self-employed. They are often starved of desperately needed loans; that’s why we need public investment banks with a specific mandate to lend the self-employed cash. Such banks would also address the injustice of being denied a mortgage. A set time-limit for settling invoices must surely be introduced, with fines for failing to pay up without reasonable cause. Self-employed people need provision for pensions, paid sick leave and holidays too. As the RSA report points out, universal credit may well leave self-employed people even more penalised by the social security system: another cause that needs taking up.

Self-employment should not mean financial hardship, a lack of basic rights and security, a race to the bottom in terms and conditions; but that’s what it does mean for many. The Tories have been allowed to crow, unchallenged, about the self-employment boom. They heap praise on the go-getters who are often getting little. On the left as well as the right, this cause has been unjustly neglected for far too long.