Riders for the food delivery company Deliveroo lost a bid to join a union in Britain on Thursday as the UK Court of Appeal ruled that they are self-employed.

The court unanimously dismissed an appeal by the Independent Workers Union of Great Britain (IWGB), which had sought to represent the drivers from north London on issues of pay, working hours and holiday.

The ruling comes as the app-driven meals delivery company staves off criticism over its treatment of its riders, which has damaged its reputation with institutional investors and its share price.

Lord Justice Underhill dismissed the union's application for collective bargaining rights, saying the drivers were "genuinely, not under an obligation to provide their services personally and have a virtually unlimited right of substitution".

He added as the riders were not employed by Deliveroo, they did not "fall within the scope of the trade union freedom right".

Both the Central Arbitration Committee, a government body which oversees labour laws, and the High Court had previously found the riders were self-employed.

Deliveroo said it was "good news" for riders and an "important milestone".

"Our message to riders is clear. We will continue to back your right to work the way you want and we will continue to listen to you and respond to the things that matter to you most," a spokesperson told AFP.

"Those campaigning to remove riders' flexibility do not speak for the vast majority of riders and seek to impose a way of working that riders do not want."

Shares in the company, which started trading on the London Stock Exchange in March, closed 9% higher after the ruling.

IWGB president Alex Marshall hit out at the decision and said Deliveroo's talk of "being your own boss" amounted to the "flexibility of choosing when to make poverty wages and work in unsafe conditions".

Saying that the union would "now consider our legal position" he added it would "continue to grow in numbers and fight on the streets until Deliveroo give these key worker heroes the pay".

Both ahead of Deliveroo's stock market float and after, riders in Britain, Australia and France have staged small-scale protests and strikes over working conditions.

In contrast, the US ride-hailing giant Uber announced in May an agreement with a British trade union to represent its 70,000 drivers in the UK, after a court ruling granted them workers' rights.

 - AFP