A car thief who was secretly recorded boasting that he had killed a police motorcyclist must serve at least 18 years in jail, a judge has ruled.
Pc Walker was killed when he was thrown from his motorcycle
Nicholas Walters chased Pc Malcolm Walker to his death through the streets of Birmingham, repeatedly ramming into his motorbike with a stolen car.
Walters was jailed for life in December 2002 for the murder of Pc Walker.
At the High Court in London Mr Justice Jack said 18 years was the appropriate minimum term under new rules.
He said he had read a letter from the officer's wife "as to the effect of his death on her and their children".
The constable was killed after responding to reports of a stolen car which he saw speeding through a red light in October 2001.
He was thrown from his bike and impaled on a concrete bollard in front of motorists waiting in a traffic jam.
Walters, of Villa Road, Lozells, Birmingham, drove off after smashing into the rear of the motorcycle.
He was later caught on a covert police recording talking about the incident.
The judge at his trial at Nottingham Crown Court described how Walters had displayed "no remorse in covert tapes".
The 18-year term is the least Walters must serve before he can be considered for parole.
Then the parole board must be satisfied he no longer poses a risk to the public.