The company behind the Yellow Pages has been accused of gaming a major customer review website to get better scores.

Yell, which sells online listings and marketing services to businesses, is giving staff cash rewards if they convince clients to leave positive reviews on Trustpilot.com.

But the policy has sparked an investigation by Trustpilot after Yell staff were told to only seek positive write-ups.

Investigation: Yell is giving staff cash rewards if they convince clients to leave positive reviews on Trustpilot.com

Trustpilot rules say a firm 'may not selectively invite users to submit reviews; as a general rule, the company must invite all or none of its users'.

But a leaflet distributed to salesman at Yell, which faces complaints from businesses for shoddy service and rip-off prices, tells them: 'For every happy customer you speak to, ask them if they mind writing a review on Trustpilot.

'If there's any risk that customers may leave a negative review, please don'