A high ranking Surrey Police officer is being investigated after it emerged he ran this year's London Marathon using his son's application.

Chief Superintendent Guy Darby, 47, was discovered to have run the race using his son Sean's entry and his performance has been declared void by organisers of the marathon.

Surrey Police's Professional Standards Department (PSD) was tipped off by another member of staff who used an anonymous reporting line to inform them of Mr Darby's actions and officers then contacted the race's organizers.

"Surrey Police takes allegations of dishonesty very seriously and will investigate thoroughly to establish the circumstances before deciding if any action needs to be taken," said a Surrey Police spokesman. "This investigation is ongoing and, therefore, we cannot provide further specific details at this time.

"PSD investigations are routinely conducted while an officer is still in post, unless there is a specific reason to justify suspension, such as a risk to the public."

A spokeswoman for Flora London Marathon added: "Guy Darby took part in the 2008 Flora London Marathon and ran under the number that was allocated through the ballot entry system for his son Sean Darby.

"Therefore we have removed this result from the results database for 2008 and this performance is now void'."

The officer was the subject of controversy when he was spotted using his mobile phone while driving by a member of the public in 2006. He escaped prosecution because he was not seen by a police officer but later apologized.

The high-ranking officer joined Surrey Police in 1983. He was appointed divisional commander for East Surrey in September 2005.