A man has been arrested after a policeman once nicknamed RoboCop for his work on a city estate was injured in a hit-and-run collision.
Pc Diederik Coetzee, from Nottinghamshire Police, was struck by a car from behind as he cycled along Blidworth Lane in Nottingham.
The 54-year-old, who joined the force in June 2001, was off-duty when the incident happened at around 6pm on Friday. Police said he was wearing a high-visibility vest and had his bike lights turned on.
A force spokeswoman said a 32-year-old man had been arrested on suspicion of dangerous driving, failure to stop at the scene of a collision and failure to report a crime.
Pc Coetzee remains in a critical but stable condition at King's Mill Hospital in Nottinghamshire, she added.
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.
Hundreds of messages of support and well wishes from the public have flooded into Nottinghamshire Police for him and his family since the collision.
The force spokeswoman said that along with a surge of goodwill from his colleagues, the switchboard at headquarters at Arnold has received scores of calls from concerned members of the community.
Phone operator Martin Sharpe said: "We have been inundated with calls from people wanting to pass on get well soon messages to Diederik. It is extremely heart-warming to hear them. He is obviously a very popular man and people are very worried about him."
Police have been examining CCTV footage, visiting mechanics and scrap metal dealers and speaking with local residents as part of their investigations. Witnesses or anyone with information about the collision are urged to contact the Crash Investigation Team on 101 extension 800 2225 or call Crimestoppers anonymously on 0800 555 111.