David Tennant joins cast of third series of prison drama Time

Jimmy McGovern's prison drama Time will return for a third series, with David Tennant joining the cast. The new run is set inside a young offenders institution and explores the lives of teenage inmates and the staff responsible for them. It examines violence, guilt and the struggle for redemption in the justice system.

Tennant plays a correctional manager, a prison officer who works at the institution. He said the drama examines a corner of society that people often like to look away from. He admitted he had not known a great deal about young offenders institutions before taking the role and said that was part of the reason for telling the story. As a society, he said, people are happy to lock others up and forget about them, but the series asks what happens to these young men, really children, who are put into the institutions and what society's responsibility is to them.

Tennant also linked the subject to his own family. He said he thought about what it would do to him at that age, or more painfully what it might do to one of his own children, because everyone makes mistakes and everyone has to answer for them. The series looks at pressure on staff. Tennant described prison officers as working in an impossible situation, understaffed and underfunded, dealing with people at pivotal moments in their lives. He said the aim is to defuse situations and keep violence out, though he had heard from officers who had been assaulted. He added: 'We send people to prison not just to punish them, to rehabilitate them, to give them a second chance and that's even more important when you're talking about lads at this age.'

The interview also covered lighter television topics. Tennant was asked about his former co-star Michael Sheen's appearance on Celebrity Traitors. He said Sheen was playing it well so far by keeping his head down and not pushing himself. Asked how to tell if Sheen is lying, Tennant said you have to assume he always is. He also commented on Richard E. Grant's 'I am a traitor' moment in last year's Thursday Murder Club, calling it either genius or a little bit bonkers. Tennant said he would be fascinated by Celebrity Traitors but thought he would struggle because he is not a good liar and finds lying panic inducing.