Meta told the Competition and Markets Authority (CMA) it would remedy a situation which would allow it to develop and improve its own products in competition with its advertisers.

The regulator said the promise came after it launched an inquiry two years ago, which found that Meta was able to use data from its advertisers against them.

“For example, data derived from users’ engagement with ads on Facebook could provide Meta with knowledge as to whether a user is interested in a particular product such as trainers, which could then in turn feed into a decision to show listings for shoes to that same user when it opens the Facebook Marketplace tab,” the CMA said on Friday.

Meta is by some distance the largest supplier of digital display adverts in the UK, earning between £4bn and £5bn in this country alone in 2021, the regulator said. More than 10 million advertisers actively use its services across the world.

Michael Grenfell, executive director of enforcement...