TripAdvisor could be misleading travellers and ruining holidays by failing to stop fake reviews boosting top-rated hotels.

Consumer watchdog Which? looked at almost 250,000 reviews on the site's top 10 ranked hotels in 10 popular tourist destinations and found one in seven had suspicious looking reviews.

Which? Travel reported 15 cases to TripAdvisor and the website admitted that 14 of them had already been caught with dodgy reviews.

Six of the hotels had been penalised for breaching guidelines, while two had been given a "red badge" - the site's most serious penalty - but this wasn't made clear to travellers.

One of the hotels looked at by Which?, rated the 'best hotel in Jordan', had 730 five-star reviews removed by TripAdvisor shortly it was contacted by the watchdog.

At the 'best hotel in Cairo', 79 per cent of the five-star reviews were left by profiles with no other contributions on the site - often a clear indication of fake reviews. Many of the reviews were removed after the investigation, meaning the hotel lost its best hotel status.

Even the humble Travelodge raised suspicions - almost half of the hundreds of five-star reviews for two Travelodges in London came from first-time reviewers who hadn't left reviews anywhere else.

TripAdvisor said it has a team of fraud investigators which works tirelessly to protect the site from fake reviews.