A trade union is hoping to sign up more than 100,000 self-employed workers within the next five years as part of a radical new project to overhaul rights for surging numbers of freelancers, and tackle plunging union membership.

With self-employed workers unlikely to take industrial action, the new platform is steering clear of the traditional role of a trade union. Instead, the main focus is late payments, one of the most pressing issue for freelancers and small businesses, with ambitions to eventually offer “bread funds” for holiday and sick pay as well as mortgage guarantees.

The project is the brainchild of the Community trade union and IndyCube, a cooperative which provides low-cost desk space in more than 30 locations, mostly in Wales, with its first London location opening this week in Walthamstow.

Walthamstow MP Stella Creasy, a champion of the project, said she hoped it would act as a gateway for promoting trade union membership among the 15% of her north-east London constituency who are now self-employed.

Creasy, who won the new union the backing of the Co-operative party, called it “a new Marxist revolution, putting the means of production in the hands of the workers”.

She said: “If Labour is going to be a party for the 21st century, it has to show it can shape the 21st century, not just fear it. We can make self-employment work for people. The answer isn’t to say that this is taking away people’s power, it’s talking about new ways to give them power back, through solidarity and collective action.”

New members are signing up in more of a trickle than a flood, with about 200 joining in the first month of the scheme, most of them with direct connections to IndyCube offices in Wales. The ambition is huge, however, with a target of 100,000 members in five years.

Speaking to the Guardian in IndyCube’s Swansea hub, Mark Hooper, the social enterprise’s founder, said he believed the worst practices of worker exploitation were creeping back as self-employment rose.

“There is a fight on, there really is. Almost everyone at one point who has been self-employed was probably earning nothing or well below minimum wage,” he said. “Independent workers are asked if they want work to take on something for free first, and then they feel they have to do it. We’re going back to exploitative practices of 100 years ago, and people are so vulnerable. This is an old way of tackling a new problem.”

Most initial members are young creative freelancers or small businesses owners, but in the medium term, Hooper said the project’s ambition was to attract anyone self-employed, from hairdressers to electricians and taxi drivers.

To tackle late payments, the trade union membership will include a factoring service, normally only available to large corporations, for a smaller-than-average fee of 1.4%, which means freelancers are guaranteed every invoice will be paid on time.

Hooper said small businesses and freelancers in the UK were currently £26bn out of pocket because of late payments. R3, the insolvency trade body, says that is the primary or major cause for almost a quarter of bankruptcies in the last 12 months.

“We could end late payments, we have got the solution to do it. If everyone self-employed joined today, £26bn comes back into the UK economy, it’s that simple,” Hooper said.

One of the earliest signups in IndyCube’s base in Swansea was Eifon Jones, a video producer, who admitted to initially being wary of the term “trade union” – saying he preferred the idea of being in a community. “I’ve been generally lucky with clients but if ever anyone did take the piss my position would be quite delicate. I have two kids, I can’t afford to be on the wrong end of the 60 days,” he said.

Legal assistance from the union was also a draw for Jones, having once almost taken out Cesc Fàbregas with a tripod after doing some work for Arsenal football club. “That would have been a huge claim. Millions! It’s good to know you wouldn’t be on your own, facing that,” he said.

Jones said his own family had been sceptical. He said: “I mentioned it to my dad, that I was becoming part of the union and he said, ‘you going to go on strike then?’ But there’s lots that could evolve from being in a collective. I pay £50 a month to use Adobe Creative Cloud, but if the union got big enough, you could buy it in bulk and not have to pay as much.”

The challenge of convincing young self-employed professionals that trade unionism is relevant is a huge challenge, says Lauren Crowley, Community’s research and policy officer.

Latest figures show unions have experienced the biggest membership drop since records began, losing 275,000 members last year to slip to 6.2 million. Unions have traditionally viewed the rise of the gig economy and self-employment as a slow erosion of traditional workers’ rights, blamed in part for the 4.2% drop in union membership.

But there is a unique appeal to a union, with more than just practical benefits. Several of the original signups who spoke to the Guardian in Swansea, as well as local freelancers attending the launch of the Walthamstow office, said they were primarily attracted to a very traditional union value: the idea of a having a national voice.

In south Wales, Anne Collis, who runs the Barod cooperative, said the main draw was “the idea of being part of something bigger. It is very isolating, working on your own.” Zoe Shehadeh, who co-runs Swansea Surveys, said it was “the idea of being part of a community – that you aren’t alone”.

Rosslyn Postlewaite, a freelance illustrator who attended the Walthamstow launch, said self-employed workers could feel vulnerable liaising with difficult clients. “You can get advice by just searching Google, but actually, having some experienced people in an network gives you a lot more confidence,” she said.

Both Hooper and Crowley see the creation of the new system as vital preparation for a radical new future of employment, with the rise of automation and flexible working. “When the mining industry was shut down there was nothing for workers, no support or anything,” Crowley said. “But I don’t see big political parties thinking about this on any major level. Trade unionism going back hundreds of years has been about giving power back to the workers – and that’s what this is about.”