Apple tried to conceal documents showing it deliberately degraded the performance of old iPhones, a tribunal starting this week will hear, in a move that, if successful, could leave millions of consumers in the UK in line for compensation.

On Friday, the UK’s Competition Appeal Tribunal will hear lawyers for a class action argue the tech giant is trying to avoid releasing information that they say shows it chose to use software updates to ‘throttle’ older iPhones to conceal problems with their batteries.

They argue Apple is trying to hide this from UK consumers by claiming commercial sensitivity.

Apple has hit back, saying it is entitled to keep commercially sensitive information out of the public domain on legal grounds.

The tech giant, led by Tim Cook has repeatedly tried and failed to have the case thrown out since it was launched in 2022, with a hearing taking place next year.

Lawyers believe that the claim could cost Apple as much as £956million if it is successful and leave 21million people who used iPhones 6s, 6s Plus, SE, 7 and 7 Plus in line for a payout. It is estimated each person could receive £40 in compensation.

It follows a similar case in the US which was settled by Apple in 2020 with a compensation fund of about $500 million, although it did not admit any liability.

Consumer campaigner Justin Gutmann, who is leading the UK class action, told The Mail on Sunday: ‘My claim alleges, on behalf of millions of iPhone users, that Apple abused its dominant position. An important aspect of that abuse was it was not transparent with customers.

‘It is hard to understand why, years later, Apple is still trying to keep evidence out of the public domain.

‘If Apple has good reasons for its conduct, it should make those arguments openly in court as any other defendant is required to do.’

An Apple spokesman said: ‘We have never – and would never – do anything to intentionally shorten the life of any Apple product or degrade the user experience to drive customer upgrades.

‘Our goal has always been to create products that our customers love, and making iPhones last as long as possible is an important part of that.’