Public transport firm Arriva is playing down concerns over safety after receiving an official complaint over employees using mobiles phones while driving buses.

A worried passenger, who does not want to be named, said he first contacted Arriva on December 6, 2001, when he noticed a driver using a mobile phone in Totteridge Road.

Arriva told the man, from Totteridge, High Wycombe, that the driver's behaviour was unacceptable and that he had been disciplined. But since then, the passenger said he has seen two more incidents. He said: "If in 14 months I have seen three incidents, then there are certainly many happening every week."

He contacted the bus company again last September when he saw the driver using a phone in Tylers Green. And last Thursday, the man said he noticed another driver using a mobile while driving in Castle Street.

He said: "Indeed the driver carried on using his mobile phone whilst issuing tickets to passengers when he stopped to pick up passengers."

The man spoke to the drivers on the last two occasions he saw them use a mobile phone. He said: "In both cases they did not seem to believe that they were doing anything wrong and defended their actions."

The man has now made a formal complaint to Arriva regarding what he calls repeated breaches of their health and safety policy and breaking the Highway Code.

The resident has also complained to traffic police, High Wycombe MP Paul Goodman and the Health and Safety Executive.

The bus company's managing director, Heath Williams, said: "At Arriva the Shires and Essex we take the safety of our customers and employees very seriously.

"Mobile phone use when driving is not tolerated and is subject to disciplinary procedures. All our bus drivers are aware that mobile phones should not be used whilst driving."

He added: "Although every incident is taken seriously, it is clear from the very few incidents that are reported that the majority of bus drivers follow company policy. However, some individuals have used their phones and, where this has been reported to us, we have taken the necessary action."