Ringer is the 18th episode of The Bill. Accidents can happen, but the boys from Sun Hill know that they are not always what they seem.
There is a serious road crash involving a Porsche, a motorcycle, a coach, a lorry and a Cortina resulting in six deaths. The Porsche had been tampered with prior to the accident and turns out to have been made of three different cars. Brownlow sets up a temporary morgue at a local school; W.P.C. Martella and P.C. Muswell have the job of informing relatives of the deaths. After following the trail from the Porsche, D.I. Galloway raids a scrapyard only to find D.S. Burnside from the robbery squad undercover as a buyer, about to break the ring, but having forgotten to tell Galloway.
- Colin Blumenau as P.C. Edwards
- Ralph Brown as P.C. Muswell
- Nula Conwell as W.P.C. Martella
- Ronny Cush as P.C. Lyttleton
- Larry Dann as Sgt. Peters
- Peter Ellis as Chief Supt. Brownlow
- Trudie Goodwin as W.P.C. Ackland
- Ashley Gunstock as P.C. Frank
- Robert Hudson as P.C. Smith
- Jon Iles as Det. Con. Dashwood
- Roger Leach as Sgt. Penny
- Eric Richard as Sgt. Cryer
- John Salthouse as Det. Insp. Galloway
- Tony Scannell as Det. Sgt. Roach
- Jeff Stewart as P.C. Hollis
- Chris Walker as P.C. Shaw
- Mark Wingett as P.C. Carver
- Christopher Ellison as Sgt. Burnside
- Andy Rashleigh as Det. Sgt. Rigby
- Mike Savage as Traffic Patrol Sgt.
- Lavinia Bertram as Helen Crisp
- Peter Pacey as Julian Proctor
- Garry Freer as Hospital Technician
- Michael Melia as Mr. Kaye
- Ken Wynne as Mr. Wilshire
- Jane Lowe as Mrs. Simpson
- Marian McLoughlin as Linda
- Arthur Blake as Lionel Galley
- Mark York as Terry Sidwick
- Eileen Davies as Miss Potts
- Heather Tobias as Mrs. Lockett
- Tommy Boyle as Dave Collins
- Rita Davies as Mrs. Davis
- Dave Holland, Greg Powell, Paul Heasman, Graeme Crowther and Steven Whyment as Villains
- P.C. Robin Frank returns to duty in a deskbound capacity while recovering from the bullet wound sustained in "Hostage".
- This is the first episode of The Bill in which the entire regular cast appears.
- Second of three Guest Appearances by Christopher Ellison as Sgt. Burnside. He joins the regular cast in Series 4.