TRIPADVISOR failed to spot three fictitious holiday listings on its website even after they were pushed up the rankings using obviously fake reviews in an investigation that has exposed how easily customers can be conned on one of the world?s biggest travel sites.

Two bogus B&Bs and a non-existent walking tour of London appeared alongside genuine UK listings for more than two weeks, during which time they accumulated 18 reviews.

These reviews, like the listings, were fake and commissioned by Which? Travel magazine, to highlight how TripAdvisor was ?clearly failing? to protect its customers from such sharp practices.

Its researchers paid fake reviewers to push their fictitious listings up the local rankings and then posted negative reviews to push them down again.

The disclosure comes amid growing concerns over the reliability of online reviews after an undercover investigation by The Sunday Times showed that fake paid-for recommendations could be used to secure a top spot on an Amazon bestseller list.

After our revelations, Amazon sued 1,114 fake reviewers in the US courts, citing ?manipulation and deception? of their customers.

In its investigation into TripAdvisor, which boasts 38m unique visitors a month,Which? Travel took less than an hour to create listings for two B&Bs, supposedly in Surrey and Scotland, and a London walking tour starting at Trafalgar Square.

For each one all they supplied to TripAdvisor was a website, postal and email address, telephone number, credit card details and a fake name. In one case they didn?t even give a real address; just a postcode and town. Yet TripAdvisor cleared all three listings within a few days.

A small B&B was praised by a fake critic for having its own pool (Altrendo images)

Which? then placed an advert on a site where review-writing services are bought and sold and received more than 50 responses. The chosen applicants were each paid between ?2 and ?3 for their fake reviews, which were often poorly written.

One review for the Scottish B&B, which was listed as being deep in the Highlands, described it as ?perfect if you?re staying in the capital?, adding: ?The 24-hour security made us feel safe in an urban setting like this . . . and the concierge helped us find the best seats in the theatre up the road.?

Even though it was supposed to be a small B&B, they also praised its ?health club?, ?swimming pool? and ?new in-house Italian restaurant?.

Of the 54 reviews commissioned by the researchers, 18 were posted and only a few were taken down before the end of the investigation.

After just one fake review, the businesses started climbing TripAdvisor?s rankings. The fake walking tour leapt to No 392 out of 505 in the Tours and Activities in London, on the back of one ?very good? review, while the Highland B&B rose to third out of the four in its area.

Similarly, one negative ?terrible? review was all it took to send them plummeting back to the bottom again.

The researchers also wanted to test how effective TripAdvisor was at removing a damaging fake review and so reported one of the less plausible one-star comments they had added to one of their fictitious B&Bs to the site?s content-checkers.

The fake complainant had written: ?On two days we had . . . to make do with wash from a kettle.?

Even though both the review and the B&B were fake, TripAdvisor ruled that the posting complied with its guidelines and refused to remove the comment.

Mike Avery, who owns Cromwell?s bar and restaurant in Shrewsbury, experienced the reality of being targeted by an anonymous fake reviewer. In 2012 his business received a string of damaging one-star reviews, including one reading ?eat here and die?, as part of a suspected blackmail campaign.

Avery claimed that he had to report the posts to police before TripAdvisor finally took them down.

The former managers of The Bell, in Oxfordshire, graded their own hotel

?They were up there for a few weeks, during which time the distress was significant and I even considered selling up,? he said. ?It?s no exaggeration to say that negative reviews like that can break a business.?

Avery has now been asked to submit evidence to the Federal Trade Commission, the American business watchdog, detailing his experiences with TripAdvisor.

Matt Stevens, senior researcher for Which? Travel magazine, said: ?TripAdvisor makes millions in profits from a business model which relies on your trust, yet its fraud detection systems and fake-review penalties are clearly failing. Until it creates a more thorough vetting process, the truth is you can?t trust TripAdvisor.?

The site is also facing a growing backlash on social media over its failure to root out fake reviewers. Last week a campaign was launched under the hashtag #noreceiptnoreview to force TripAdvisor to use only verifiable customer reviews. TomEats, a Twitter user who claims to be a restaurant inspector, posted an open letter to the company from the ?TripAdvisor community? saying: ?Without a valid receipt no review . . . should be deemed trustworthy.?

A TripAdvisor spokeswoman claimed 90% of the reviews submitted in the Which? Travel investigation had been detected and removed, and that the figure would have been much higher in a ?real-world situation?.

?Most fraudsters are only interested in trying to manipulate the rankings of real businesses ? so naturally that is what our content specialists are focused on catching,? she added. The company said its systems and processes were ?extremely effective in catching and removing attempts at fraud?.

@robin_henry

Ringing their own bell

Some businesses resort to professionals to write fake reviews, but others do it themselves, writes Robin Henry.

The Bell hotel and bar in Charlbury, Oxfordshire, enjoyed a series of glowing reviews from TripAdvisor users ?Colm R? and ?Tracy R? last year. In reality the accounts belonged to Colm and Tracy Reilly, the hotel?s former managers. One of Tracy R?s five-star reviews even included their email and website address.

Trip?Advisor prohibits businesses from posting reviews or including promotional links, yet the posts remained on the site for nearly a year.

Last week TripAdvisor removed the reviews and launched an investigation.

The Bell has been under new management since the spring and the new proprietors had no part in the reviews. The Reillys declined to comment.