A bicycle courier has won an employment rights case in a ruling which could have far-reaching implications for self-employed people working in the so-called “gig economy”.

A tribunal found that Maggie Dewhurst, a courier with the firm City Sprint, should be classed as an employee rather than self-employed, entitling her to basic rights such as the minimum wage and holiday and sick pay.

The decision will only apply to Ms Dewhurst, but is the first of four legal challenges being taken against courier companies, including Addison Lee, Excel and eCourier.

It indicates the legal tide may be turning against big firms in the service sector classifying their full-time workers as self-employed, and follows a similar ruling against Uber last July.

Friday’s decision highlights the practices of the “gig economy”, where people are employed by companies supposedly on a “job-by-job” basis – but in practice, are often subject to the same terms and conditions as employees.

Ms Dewhurst, 29, from South London, who has worked for the firm for two years making healthcare deliveries, argued her role was not like that of a genuinely self-employed person because she could not “pick and choose” which jobs to accept.

“We spend all day being told what to do, when to do it and how to do it. We're under their control. We're not a mosaic of small businesses and that's why we deserve basic employment rights like the national minimum wage,” Ms Dewhurst said.

She said after the judgement: “I'm delighted that the tribunal ruled in our favour as it has set a legal and moral precedent which others can use to make similar claims.

“This wasn’t just about me. It was about people who have been working here for 20 years without any of these rights.

“They argued that we weren’t part of the company, but you cannot run a £14.5 million courier business without employing a single courier.”

The tribunal found that City Sprint had unlawfully failed to pay Ms Dewhurst for two days’ holiday to which she was entitled.

The judge, Joanna Wade, described City Sprint’s contractual arrangements as “contorted”, “indecipherable” and “window-dressing”.

City Sprint said it was “disappointed” with the ruling, which it would review “in detail” before deciding whether or not to appeal.

The firm, which has 3,500 couriers nationwide, claimed it enjoyed “a good relationship with our fleet” and said that evidence given at the tribunal highlighted that it is “a good company that pays its couriers some of the best rates in the industry”.

The company called on the government to clarify the terms and conditions of self-employment in light of this and similar rulings.

It said: “This case has demonstrated that there is still widespread confusion regarding this area of law, which is why we are calling on the government to provide better support and help for businesses across the UK who could be similarly affected,”

Uber is currently appealing a tribunal ruling which found workers were entitled to the same rights as full-time employees because it claims it is a technology company rather than a taxi firm.

Paul Jennings, a partner at law firm Bates Wells Braithwaite, which represented Ms Dewhurst, described the ruling as “legally and ethically the right outcome”.

He said: “Until now couriers have occupied a vulnerable position. They carry out physically demanding work, in dangerous conditions, but cannot take paid leave.

“In the wake of this judgement, we expect to that thousands of couriers across the capital will look to assert their rights and seek back pay.”

The Independent Workers Union of Great Britain, which campaigns for better rights for self-employed people, organised a campaign of protests against City Sprint in 2015, including picketing, contacting their clients and publicity stunts.