Britain's Court of Appeal confirmed on Thursday that riders for food delivery firm Deliveroo were self-employed, dismissing a union appeal against past judgments on their status.
Deliveroo said it was the fourth court judgment in Britain which had determined its riders were self-employed, after one by the Central Arbitration Committee and two at the High Court.
The Independent Workers Union of Great Britain (IWGB) was refused permission in 2017 for collective bargaining rights for a group of Deliveroo riders on the basis that they were not workers under the terms of legislation on labour relations.
Employment models across the "gig economy" have been challenged in courts around the world by unions and workers.
In February, Britain's Supreme Curt ruled that a group of Uber drivers were entitled to worker rights such as the minimum wage.
In Thursday's unanimous 3-0 verdict, the Court of Appeal upheld the High Court's dismissal of a judicial review of that judgement.
It said the fact that Deliveroo's riders did not have an obligation to provide services personally was a material factor.
A Deliveroo spokesperson said the verdict was an important milestone.
"UK courts have now tested and upheld the self-employed status of Deliveroo riders four times," the spokesperson said.
"Deliveroo's model offers the genuine flexibility that is only compatible with self-employment, providing riders with the work they tell us they value."
The risk of legal challenges to its employment model was one reason that some major investors shunned Deliveroo's London listing in March.
The shares, which were sold for 390 pence in the IPO, rose as much as 9% on Thursday to a high of 274 pence, the highest level since April.
Britain's opposition Labour Party said the decision was devastating for Deliveroo drivers, and the government should outlaw the company's "exploitative employment practices".