The four-part series, which began on Monday, sees model Penny Lancaster, Made in Chelseas Jamie Laing, TV presenter Katie Piper, Goggleboxs Sandi Bogle and comedian Marcus Brigstocke volunteer as special constables with the force in the county.Over the four episodes, celebrities will get to grips with the training, and effort required to be a volunteer within the Cambridgeshire force, facing tough situations. The first episode, which aired on Monday, saw the five celebrities undergo intense training, learning how to become efficient as well as assertive whilst on the beat. In one scene, Penny Lancaster is faced with confronting her demons from her past as she chases after a robber on her own. In the episode, Penny is split from the special constable with whom she is working in a bid to catch two women who are said to have robbed a store in Peterborough. As Penny chases the suspect, she is threatened with being stabbed with a needle, but she is undeterred and is able to catch and arrest the person with back up from her team. Also featured is Katie Piper, a TV presenter who, 11 years ago, was a victim of an acid attack as she left her house, leaving her with life-long injuries. In the series, Katie struggles to conquer her fears, while Jamie Laing, the Made in Chelsea and Big Brother star, steps up to the challenge of bringing down a potentially dangerous suspect. Jamie is called to a shop in Peterborough, where reports of a man running around with a weapon had been made. Jamie and his team chased the suspect and managed to hold him to the ground and arrest him. As the series progresses, the famous faces will be shown responding to real 999 calls, working in custody, as well as taking part in raids. Assistant chief constable Dan Vajzovic said: This is a great opportunity to give viewers a chance to see some of the excellent work our officers do day in, day out. The series promises to be entertaining and impactful, offering the viewer a unique view of the role volunteers play in policing their own communities. The show will return on Monday on Channel 4 at 9pm.