The explosive memoir from ex-MI5 surveillance officer Tom Marcus, I Spy takes you on a non-stop, adenalin-fuelled ride as he hunts down those who would do our country harm.

'The brutal truth about the war against terror. Fast-paced and gripping' – Ant Middleton, author of First Man In

Tom spent years working covertly to stop those who want to do us harm. In his bestselling memoir Soldier Spy, he told how he was recruited and described some of his top-secret operations. In I Spy, he takes us deeper undercover as he puts his life on the line once more.

Tom and his team race to prevent terrorists from causing carnage on our streets and outsmart Russian agents, blocking a daring plot that threatens the security of the nation. Relying on their quick wits, training and courage, the extraordinary men and women of MI5 are under intense pressure every day.

Not everyone is suited for the work, and Tom shows how the incredibly tough challenges he faced growing up gave him the mental strength and skills to survive in a dangerous world.

Gritty and eye-opening, this is a unique insight into a hidden war and the sacrifices made by those who fight it. You will never take your safety for granted again.

'One of the most successful MI5 undercover surveillance officers of his time' – Sun