Britain's biggest travel review website, whose critiques of hotels and restaurants can include damning references to Basil Fawlty-style hotel managers, bed bugs and stomach-churning meals, is facing potential legal action from hundreds of hoteliers and restaurateurs who claim their businesses are being damaged by malicious and unfounded reviews.
More than 400 establishments have indicated they may join a "group defamation action" against TripAdvisor, which carries "unbiased" reviews, written by members of the public, of hotels and other businesses.
Unless the popular site removes the most wounding criticisms within a fortnight, legal proceedings could begin shortly, according to KwikChex, a Bournemouth-based reputation management firm, which is canvassing support for a case.
According to KwikChex, many of its clients suspect disobliging reviews are invented or exaggerated, or posted by business rivals using online anonymity to damage successful competitors. When contacted by individual owners, TripAdvisor had been "overwhelmingly hostile and intransigent" even if presented with evidence casting doubt on specific criticism, according to KwikChex's founder Chris Emmins.
"Next week we will present TripAdvisor with details including some of the worst cases and ask them to make corrections. They will be given seven days to respond and, if they don't, I think it's highly likely a class action will follow," he told The Independent.
Founded 10 years ago and now owned by the Expedia travel group, TripAdvisor has become an important player in the travel industry, carrying 35 million reviews of hotels, holiday rental homes and restaurants, and is the UK's most visited travel website, according to the research firm Hitwise.
Travellers use reviews by fellow tourists to check out hotels around the world before booking – and often change plans after reading them.
One guest wrote of a hotel in Atlanta, US: "The staff was friendly but that didn't make up for the dirty bathroom and two cockroaches I saw within 15 minutes of arriving in the room."
A reviewer alleging food poisoning, at a hotel in Cape Town, South Africa, recalled: "Three of us had lunch here and within a few hours both my friend and I were suffering from severe vomiting. We had to abandon a tour booked for the next day."
About "a disgusting, filthy and dreadful" hotel in India, a reviewer advised: "Under no circumstances should anyone stay here; it's not a hotel, it's a house and it's absolutely horrible. The owner just scams money out of you every chance he gets and is all smiles whilst doing so.
"I was in the basement, words can't describe it – sleeping on the streets of Delhi is probably a better option."
TripAdvisor says it uses specialist software and employs dozens of quality assurance investigators to spot rogue postings. Users can report suspicious views and business owners can respond to any review.
During an investigation into bed bugs in British hotels last year, The Independent found unverified comments on TripAdvisor often tallied with officially-documented cases of infestation.
However Mr Emmins, who charges £170 for membership of his reputation-enhancement services, said that many withering comments turned out to be unfounded when subjected to closer scrutiny.
"We checked 100 reports that supposedly had food poisoning: no one had reported it to the local authority. Food poisoning is a complicated issue: it could have happened at home," he said.
"There are several reviews that claimed the manager assaulted them or punched them – allegations of racism and sexual assault."
He objected to it sending out emails naming individual establishments as "Horror Hotels" because – he claimed – the majority of reviews about them were often positive. "I was a fan of TripAdvisor and and customer feedback is a great thing, but I think they have got to be upfront about how reliable the material is," he said.
"If they don't authenticate the reviews then I think that should be absolutely clear. They should say: 'We can't confirm this person's report', but instead it says: 'Trusted reviews' or 'TrustedTripAdvisor'. That would be much better for the customer."
TripAdvisor declined to comment on threatened litigation, but defended the accuracy of its reviews. It said: "We believe our more than 35 million reviews and opinions are authentic and honest from real travellers, which is why we enjoy tremendous user loyalty and growth. If the reviews people read didn't paint an accurate picture, users would not keep coming back."
It added: "Our advice when reading through the reviews of a property is to throw out the anomalies that appear overly critical or overly complimentary. What is left is the collective wisdom of the community."
Case study: 'They should have the courtesy to look into complaints'
Hotelier Louis Naudi says TripAdvisor has published a number of malicious and false reviews of his establishment, The Royal Sportsman in Porthmadog, Wales.
A "terrible" review posted in April, by "Iva8" from Italy, complained: "The front desk was manned by unhelpful sour faced owner. The room stank of mould and was dark and unpleasant ... the food was awful and expensive."
Another disobliging reviewer listed the hotel's "negatives" as "owner's dog urinating on grotty carpet at desk as we checked in" and "inedible fish main course", concluding: "Overall poor value and would not recommend."
Provided they are justified, Mr Naudi says he does not mind mixed or bad reviews as they give him an opportunity to rectify problems and fine-tune service, but he resents what he says are untrue or personal attacks.
The Royal Sportsman has a good reputation on TripAdvisor, judging by the 95 reviews, 38 of which rated it excellent, 29 very good, 13 average, 7 poor and 8 terrible. Eighty per cent of customers recommended the small seaside hotel, whose rooms costs £56 to £96 a night. One reviewer wrote on 1 September praising the hotel, its location and its food, saying it was a "really lovely place", and promising to return."
Mr Naudi, who has run the 28-room hotel with his wife Viorica for 12 years, suspects some of the bad reviews have been written by people with a grudge. He says the TripAdvisor should treat hoteliers more seriously: "When they get a complaint they should have the courtesy to investigate and respond accordingly."
Birmingham 'AVOID – I would not let my dog eat from this DISGUSTING place' Anon
Glasgow 'Blood in bath, which hadn't been cleaned for sometime... Must be the worst of the budget hotels' Anon
London 'A burger with salad and fries turned out to be cardboard, straw and some dry green stuff' Anon
Manchester 'I witnessed a member of staff eating from a customer's plate as she returned it to the kitchen' Anon
Newcastle 'By far the worst hotel I have ever stayed in... The carpet hadn't been cleaned in weeks' Anon
Cardiff 'My girlfriend was struck down by diarrhoea and, two days later, had still not recovered' Anon
London 'I'm veggie and they fed me meat! I bit into the spring roll and started heaving my guts up' Anon