TV presenter and model Katie Piper, Loose Women panellist Penny Lancaster, Made in Chelsea's Jamie Laing, Gogglebox's Sandi Bogle and comedian Marcus Brigstocke volunteer as special constables with Cambridgeshire police force. In the first edition, the gruelling first-day training forces Penny to confront demons from her past and serves as a rude awakening to everyone else of the dangers they're about to face.

Jamie Laing takes part in a raid on a cannabis farm, while Sandi Bogle opens up about a family tragedy after joining an armed unit called out to confront a man wielding a knife. When police are called to the home of an ex-soldier struggling with PTSD, Katie Piper helps the team by drawing on her own personal trauma.

TV presenter and model Katie Piper, Loose Women panellist Penny Lancaster, Made in Chelsea's Jamie Laing, Gogglebox's Sandi Bogle and comedian Marcus Brigstocke volunteer as special constables with Cambridgeshire police force. They respond to real 999 calls and work in custody and CID, as well as take part in high-risk drug raids and keep order in rowdy city centres at the weekend.

The celebrities are assigned to specialist police units for their final shifts. Haunted by events in her own past, Penny Lancaster is determined to help CID get justice for the victim of a brutal assault, while Sandi Bogle is shocked by what she discovers working with a team tackling drug crime. Katie Piper confronts her worst fears when she has to run into a burning building to help rescue residents. Last in the series.