“Unscrupulous sellers” who are offering incentives in exchange for five-star reviews are “cheating their way to the top” said consumer group Which?. It carried out the research and is now calling on online platforms to do more to tackle misleading and fake reviews.

Of those who have shopped on Amazon in the last year, 8% said they were asked by a seller to leave a five-star review in return for an incentive and 4% were offered a reward for changing a negative review into a positive review.

Some shoppers also told Which? they had changed a review after being contacted by a seller and receiving an incentive.

In one example, a shopper was offered a refund of £22 if they changed their review for a pair of pillow cases they had bought. Another was given a £50 Amazon voucher and a full refund after they left a positive review for a product.

False reviews can cause harm to consumers

Yet false positive reviews can cause harm to other consumers and can make shoppers more than twice as likely to choose poor-quality products, Which? said. The group also found that some shoppers had bought poor quality or even dangerous items after reading false five-star reviews.

In another example, a shopper had ordered a handheld vacuum on Amazon and was offered a £10 gift card in exchange for a positive review. The vacuum has 4,264 ratings on Amazon, 55% of which were five stars. Yet some reviews showed that shoppers had found dangerous faults with the vacuum.

There were also more than 100 reviews listed for the vacuum which were for a different product and 90 of these were five stars. This is known as “review merging” whereby sellers merge positive reviews of a dormant listing with another product to boost the overall number of five-star reviews it has.

Which? said that Amazon should be doing more to tackle the problem of misleading reviews and it has access to a huge amount of data to do this. It said it should act when a high volume of reviews are changed and it should investigate reviews where incentives are mentioned.

The Government is currently consulting on how to tackle fake online reviews and Which? said that hosting reviews without taking reasonable and proportionate steps to ensure they are genuine should become a criminal offence.

‘Incentives in order to cheat the system’

Rocio Concha, Which? director of policy and advocacy, said: “It’s clear that sellers on Amazon are bombarding customers with incentives in order to cheat the system and we have seen evidence that they are successfully evading Amazon’s defences.

“Amazon and other review-hosting websites need to step up and do more to banish fake reviews from their platforms by taking measures that ensure the reviews they host are genuine.

“The Government must make hosting fake reviews a criminal offence in its Digital Markets, Competition and Consumers Bill so that regulators can take strong action to crack down on the problem.”

An Amazon spokesperson told Which?: “We have clear policies that prohibit reviews abuse, and we do not allow sellers to contact customers directly about a review and offer them incentives like gift cards to alter their reviews.

“There is absolutely no place for this kind of activity and we suspend, ban, and take legal action against sellers who violate our policies. We had already taken action against the sellers identified by Which? prior to publication of the report and removed a number of reviews.

“Customers who have received direct contact from sellers offering compensation of any kind can send this evidence to Amazon by emailing report-review-compensation@amazon.co.uk with details of the product name and a photo or screenshot of the compensation offer.”