Britain’s competition watchdog, the Competition and Markets Authority, said that, after it had warned them, Facebook and eBay pledged to remove accounts, pages and groups involved in the trade of fake reviews.

“We’re pleased that Facebook and eBay are doing the right thing by committing to tackle this problem and helping to keep their sites free from posts selling fake reviews”, said the CMA’s chief executive, Andrea Coscelli.

Fake reviews look like genuine reviews, but they are paid for by the manufacturer, which is aiming to boost its rankings and sales.

The move was welcomed by consumers groups: “The regulator must now turn its attention to review sites which are losing the battle against fake reviews, with shoppers duped into buying shoddy goods and services which have been artificially boosted by unscrupulous sellers”, said a consumer group representative.

“We maintain zero tolerance for fake or misleading reviews and will continue to take action against any seller that breaches our user policies”, an eBay spokesperson said.

“While we have invested heavily to prevent this kind of activity across our services, we know there is more work to do and are working with the CMA to address this issue”, a Facebook spokesperson added. The company has already removed 188 pages and groups and disabled 24 accounts that were involved in the fake review trade.