A Northumbria Police detention officer broke a cyclist's neck and cheek when he knocked him over in his car at a roundabout.
Andrew Hayes, who works as a detention officer for the force, was off-duty when he struck the victim with his Volvo in North Shields.
The 38-year-old hadn't seen the cyclist when he pulled out at the roundabout and sent him flying to the ground, a court heard.
The male victim was left unconscious and was taken to hospital, where it was found he'd suffered a fractured neck, cheek and cuts and bruises.
He also had to have seven stitches to an injury on his chin and subsequently had to wear a neck and back brace for eight weeks, prosecutors said.
Hayes, of Biscop Court, in Holystone, has now been fined and given six penalty points after he pleaded guilty to careless driving at North Tyneside Magistrates' Court.
Oriana Frame, prosecuting, said a witness was waiting in her car at the roundabout, on New York Road, on January 17 this year when Hayes pulled up in the lane beside her.
"The defendant made eye contact with her before driving on to the roundabout and hitting [the victim] on his bike," Miss Frame continued.
"The victim remembers travelling around the roundabout and, the next thing he knows, he's waking up, lying on the ground."
Hayes, who has worked for Northumbria Police for 12 years after serving nine years in the Royal Marines, remained at the scene and called the emergency services.
The cyclist was taken to hospital, where the extent of his injuries were revealed.
Miss Frame said that the victim spent eight weeks in a neck and back brace and had to be visited by nurses twice a week for it to be cleaned and changed.
In a statement, he said: "The injuries I sustained placed my life on hold for the eight weeks that I was in a neck collar.
"I'm a very active person, so not being able to get out my house had a real effect on me."
The court heard that Hayes hadn't seen the cyclist when he pulled out as he was behind the bar between his windscreen and driver's window.
His solicitor said: "The victim was awake at first and tried to move. Mr Hayes told him not to. He then slipped into unconsciousness. Mr Hayes then phoned an ambulance and remained at the scene."
The court was told that Hayes had suffered "many sleepless nights" since the accident and was extremely remorseful.
Fining him £300 and ordering him to pay a £30 victim surcharge and £85 costs, District Judge Paul Currer said: "This momentary lapse in concentration had pretty serious consequences but, nevertheless, it was a momentary lapse."
