A policeman once nicknamed "RoboCop" for his work on a city estate remains critically ill in hospital after a hit-and-run collision in Nottingham. [November 28 2011]

Pc Diederik Coetzee, from Nottinghamshire Police, was struck by a car from behind as he cycled along Blidworth Lane on Friday. The 54-year-old was off-duty when the incident happened, at around 6pm. Police said he was wearing a high-visibility vest and had his bike lights turned on. A force spokeswoman said he was still in hospital in Nottingham. His condition was described as critical but stable.

The Mansfield South beat officer made headlines in 2005 after making hundreds of arrests in a year, patrolling Mansfield's Ladywood estate on his bike. Nottinghamshire Police said he joined the force in June 2001.

Detective Sergeant Ged Hazelwood said, "Pc Coetzee is a well known member of the Mansfield beat team and well-liked by both the community he serves and his colleagues. I would like to personally appeal to the motorist involved to get in touch. The sooner you come forward, the sooner we can get to the bottom of what happened and provide some answers to Pc Coetzee and his family."

Nottinghamshire Police's crash investigation team is examining CCTV footage from the area surrounding the scene, a spokeswoman said.

Witnesses or anyone with information is urged to contact the crash investigation team on 101 extension 800 2225 or call Crimestoppers. Crimestoppers is an independent charity and not part of the police. If you wish to pass on information about crime anonymously, please call Crimestoppers on 0800 555 111, or fill out our anonymous online Giving Information Form.