The BBC reports the case rested on the distinction between plumber Gary Smith’s status as either a self-employed contractor or a worker for the company.

Smith, who was VAT-registered and paid tax on a self-employed basis, worked solely for Pimlico Plumbers for six years. He sought to cut his five-day week down to three following a heart attack in 2010.

Pimlico Plumbers refused and took away his branded van, which he had hired. Smith also claims he was dismissed.

Smith argued that he was entitled to basic workers' rights, including the National Minimum Wage and paid holiday, and the ability to bring discrimination claims.

A previous employment tribunal ruled the company’s plumbers were workers, a status not recognised by HM Revenue & Customs, who only have two classifications – employee or self-employed – but not employees. The Court of Appeal has today upheld that decision, dismissing Pimlico Plumbers' appeal.

Employment lawyers say the appeal ruling has major implications for workers in the gig economy.

Glenn Hayes, an employment partner at law firm Irwin Mitchell, said: “We are seeing increasing numbers of individuals challenging their status and claiming to be workers or employees. CitySprint couriers and Uber drivers recently persuaded separate tribunals that they were workers and, although Uber is now appealing this, tribunals are clearly taking a pragmatic and bold approach to determining status cases, despite contractual arrangements that are designed to give the appearance that individuals are genuinely self-employed.

“The outcome of this case is very significant and could make it more difficult for Uber and others to persuade the courts that its drivers are genuinely self-employed.”

Marian Bloodworth, employment partner at law firm Kemp Little, added the judgement was unsurprising given the other recent judgments involving Uber and CitySprint workers, but does also highlight the need for legal clarity around the status of those working on a self-employed basis and in the gig economy generally.

“Pimlico Plumbers took into account HMRC guidance around the difference between self-employed workers and employees but this case acts as a stark reminder that businesses must always consider the position from an employment law perspective, as well as a tax one. Tribunals and courts are increasingly willing to look behind the labels businesses use for their staff and will take into account the reality of the working arrangements and relationships.

“Businesses and workers need certainty in how they contract with each other as this current level of uncertainty is to no-one's advantage. We hope that the Taylor review into modern working practices and other reviews will lead in due course to such clarity being provided.”