Series 5 begins with Britain left reeling after a series of terrorist attacks. Our team believe the attacks cloak a conspiracy to destroy democracy and turn Britain into a 'police state'. Can the team protect the democratic way of life? Zafar goes undercover and infiltrates a home-grown Islamic terror group who are planning a massive attack against London. There could also be serious repercussions for Ruth when she finds out the deaths of seven terrorist suspects in a prison fire were in fact staged by British military intelligence.

• Peter Firth
• Nicola Walker
• Max Brown
• Lara Pulver
• William Hope
• Alex Lanipekun
• Geoffrey Streatfeild
• Tom Weston-Jones