Consumer group Which? has launched a £3 billion claim against Apple, claiming the tech giant has breached competition law by “forcing its iCloud services on customers”.

It says Apple has encouraged users to sign up to iCloud to store photos, videos and other data and is therefore favouring its own products, while simultaneously making it difficult to use alternative products, ultimately stifling competition.

Which? says Apple does not allow customers to store or back up all of their phone’s data with a third-party provider, and users of its iOS operating system have to pay for the service when the amount of data being stored goes over the 5GB free limit.

In its claim, which has been filed with the Competition Appeal Tribunal, the consumer group also accuses Apple of overcharging users for iCloud subscriptions, partly because the company’s dominance of the market means it is difficult for new alternatives to emerge and provide competition.

The group said it is seeking damages for all affected Apple customers who have obtained iCloud services since October 1 2015, which it estimates is around 40 million people, and that individual customers could be owed an average of £70, depending on how long they have been paying for the service.

Which? has urged Apple to resolve the claim without the need for litigation by offering consumers their money back, and opening up its operating system to allow users more choice for cloud services.

Apple has been contacted for comment.

Which? chief executive Anabel Hoult said: “We believe Apple customers are owed nearly £3 billion as a result of the tech giant forcing its iCloud services on customers and cutting off competition from rival services.

“By bringing this claim, Which? is showing big corporations like Apple that they cannot rip off UK consumers without facing repercussions.

“Taking this legal action means we can help consumers to get the redress that they are owed, deter similar behaviour in the future, and create a better, more competitive market.”