Image copyright Stacey MacNaught Image caption Self-employed marketing consultant Stacey MacNaught has 10 years of experience but is still asked to work for free

"It happens all the time and not just for small things. I've been asked to work for two full weeks in exchange for the company sharing the work on social media."

Stacey MacNaught is a self-employed online marketing consultant with over a decade of experience. Yet she's still inundated with requests to work for free "for exposure".

"One agency asked me to work for free two days a month to help them keep a client.

"And if they saved the client and got a new contract, they promised to outsource the work to me - as long as I cut my day rate by 50%.

"I went through my last 12 enquiries and two of them were asking for work for free, so that's one in six."

She is not alone. As the number of people in self-employment working for themselves rises, there's also a growing concern that many are being pressured into unpaid work.

Alisa Rosenbaum used to work as an architect and says she was constantly asked to do unpaid hours: "[They] string you along, expecting work for free on the basis of 'the next big job will be yours'.

"I had a client phone up and suggest that I 'needed to do this work' for him because six months ago he paid me and didn't really need the drawing he paid me to do. So now I had to do more work for him... for free."

'Name and shame'

There were 3.3 million people working for themselves in 2001, according to the Office for National Statistics. That rose to 4.8 million by 2017. Today, one in seven workers is self-employed.

Research carried out by IPSE, the Association of Independent Professionals and the Self-Employed, shows that 43% of such workers had given away their time, rising to 86% of people in creative industries.

"We need to get to a point where that is just not seen as okay anymore," comments Jonathan Lima-Matthews, senior policy adviser at IPSE.

He does not accept that unpaid work can be acceptable in order to build a portfolio or impress a potential new client.

"It needs to be called out for what it is - it's unfair. Everybody's work has value and it's right that they should be paid for that. Its common practice in certain sectors to ask for unpaid work but that doesn't mean it's okay.

"Also, it's not great for social mobility because those without family support can't afford to gain that experience by working for free."

'Candid conversation'

Image copyright Getty Images Image caption With one in seven now self employed the fairness of unpaid gigs could come in for far greater scrutiny

IPSE wants the Office of the Small Business Commissioner to be granted more powers to crack down on repeat offenders, including being able to ask businesses to state how often they ask for free work.

The commissioner Paul Uppal told BBC 5 live's Wake Up To Money programme that he is aware of the issue and wants to do more. He's calling for self-employed people to report such requests to him so he can act.

"People are hesitant about coming forward for fear of losing future work but we really want people to come forward.

"That can be anonymously if they wish, but ideally we want them to have as much of a candid conversation about this issue as possible so that they can give us the ammunition to fire the bullets on this issue.

"The main statutory power we have is to name and shame."

'Devaluing work'

Of course people can always just say no to requests for freebies, but some workers say that a culture of free work makes it harder for everyone.

Tracey MacNaught says: "It absolutely devalues the work. If there are enough people prepared to work for free then other freelancers who need to earn a living are going to struggle to get work.

"If businesses believe they can choose to not pay for something and get the same then why would they pay for it?"

Image copyright IPSE

The Freelancer Club, a membership organisation for the self-employed, has asked both the self-employed and companies to sign a code of conduct promising never to work for free or ask people to do so.

Rob Birnie, the animator behind DBM Motion Graphics, says he has the best response to the weekly requests he gets for freebies in exchange for 'exposure'.

"My stock answer now is 'just let me check if my mortgage provider will let me pay them with that exposure that you're giving me and if they will then I'll get straight back to you.'"

As the way people work continues to evolve and the Small Business Commissioner takes an interest, the fairness of unpaid gigs could soon come in for far greater scrutiny.