An investigation from consumer group Which? has found that Facebook is failing to shut down groups where people are recruited to create fake Amazon reviews, despite stating it would do so.

In June, the Competition and Markets Authority (CMA) urged Facebook and eBay to work to prevent fake reviews being sold through their sites. Both internet giants agreed to cooperate. However, only one of the two has shown significant improvement in the time since the CMA warning.

Which? analysed 10 Facebook groups looking for people to write fake reviews. The investigation found that more than 55,000 posts were created by these groups over a one-month period. One day saw over 3,500 new posts promoting incentivised reviews, with three groups posting more than 500 times in that day.

“Our latest findings demonstrate that Facebook has systematically failed to take action while its platform continues to be plagued with fake review groups generating thousands of posts a day,” said Natalie Hitchins, head of products and services at Which?.  “It is deeply concerning that the company continues to leave customers exposed to poor-quality or unsafe products boosted by misleading and disingenuous reviews.

“Facebook must immediately take steps to not only address the groups that are reported to it, but also proactively identify and shut down other groups, and put measures in place to prevent more from happening in the future.”

These groups also showed a spike in membership. On 1 August, there were 105,669 members across the 10 groups compared to 85,647 30 days before that. One group witnessed a 75 per cent increase in members with 4,300 people joining to take its membership to over 10,000. Which? does, however, attribute the sharp rise in group members to Facebook clamping down on some of the other groups floating around on its platform and people moving over to these other groups.

The CMA’s senior director, George Lusty, has called it “unacceptable” that Facebook continues to fail to deal with groups popping back up again, stating the tech giant “must take effective steps to deal with this problem by quickly removing the material and stop it from resurfacing”.

Facebook has now removed nine of the 10 groups flagged to them by Which?, and is investigating the remaining group.

“This is fundamentally a challenge for Amazon to champion. We’ve seen in recent months how the negative experiences that come from fraudulent reviews and fake products are impacting the ecommerce giant. Being seen to lead the clean-up is a vital step in rebuilding trust with consumers as we head into one of the most frenzied shopping periods in the calendar,” said Sophie Light-Wilkinson, VP of marketing EMEA at Bazaarvoice.

“Of course, we’re not dealing with any amateur operation. These groups on Facebook are highly organised units and they are abundant. It adds even more urgency to finding a solution as we err towards an online world where consumers simply can’t trust or believe in any new products from challenger brands.

“Aside from supporting Facebook in taking these groups down, Amazon must raise awareness for the legitimate means by which it – and the whole online retail space – is able to honestly gather feedback from their customer base on new products and new brands. Sampling solutions are readily available but will lose any meaning without fast action.”