Gary Smith wanted to reduce his working days at Pimlico Plumbers following a heart attack.
The Court of Appeal agreed with tribunal that said he was entitled to basic workers’ rights although he was technically self-employed.
The decision is the latest to side with workers in a flexible workforce.
This is the highest court to consider such a case and the ruling will now be closely read by others with similar disputes, many of whom will work for businesses in the so-called “gig” economy such as Uber drivers.
The case is about the distinction between Mr Smith’s status as either a self-employed contractor or a worker for the company.
He was VAT-registered, and paying tax on a self-employed basis, but worked solely for Pimlico Plumbers for six years.
After he suffered a heart attack in 2010, Mr Smith, from Kent, wanted to cut the five-day week, which he had been signed up to work with the firm, to three.
However, the firm refused and took away his branded van, which he had hired. He claims he was dismissed.
He argued that he was entitled to basic workers’ rights – which would include the national minimum wage and paid holiday and the ability to bring discrimination claims.
A previous employment tribunal found that the plumbers were workers – but not employees. The Court of Appeal has agreed with that decision, dismissing Pimlico Plumbers’ appeal.
Being given the status as workers means that they would be entitled to more rights than would be the case if they were self-employed and taking on work on totally freelance basis.