John Kiriakou is the former head of the CIA’s counterterrorism operations in Pakistan and was the first CIA insider to publicly confirm that the Bush administration was using waterboarding.

He was imprisoned for two years for leaking the name of a covert CIA operative. He says he was imprisoned in revenge for blowing the whistle on the CIA torturing captives.

The leading two Republican candidates in the US presidential race, Ted Cruz and Donald Trump, have suggested they would use waterboarding and other controversial “enhanced interrogation techniques” against terror suspects.

John tells Matt why such techniques don't work and how he went from capturing some of the most wanted men in the World to surviving prison as a former CIA agent.

Listen back here: