He went on to negotiate for hostages in Iran and Libya. Then he was asked to negotiate in Lebanon, and knew it would be dangerous.
He was captured himself, and held in prison for nearly five years, mainly in solitary confinement.
"I was chained to the wall for 23 hours and 50 minutes a day. I had no books or papers and no natural light."
He was also tortured - beaten on the sensitive soles of his feet - to test whether he had information or secrets to pass on.
"It's extremely painful. You can't walk for a week after that."
He was subjected to a mock execution - blindfolded with a metal object pressed to his head.
"I thought they were going to shoot me," he said.
He survived by keeping mentally and physically active and living "one day at a time".
"Not thinking too far ahead, and remembering that there were many people in worse situations than myself. I still had life. I was still getting food, although the food was meagre."
It took a year and intensive physiotherapy to return to normal life back in England. Since then he's spent his time studying, writing and lecturing, and went back to Beirut a few years ago to reconcile with his captors.
His Whanganui talk will be about crime and punishment. He said the New Zealand system was modelled on the British one, which is "a total mess".
But New Zealand has been a pioneer in restorative justice, and could work towards a better system.
In the United Kingdom 90 per cent of prisoners have mental health, drug or alcohol problems. They don't get help for their problems, and are often quickly back in jail.
"Locking them up isn't solving the problem, so we have to really get to the roots of the issue."
An experimental prison in the UK town of Grendon Underwood gave prisoners intensive help with their problems, and not many ended up back in prison.
"It still defeats me why we haven't opened more prisons like that. It's initially costly but in the long term it's cheaper," Waite said.
Any change will need a change of attitude from the general public. It will also take politicians to push it along - but prison reform isn't a good vote winner.
Waite doesn't have all the answers, but he wants his lecture to get people thinking.
++ Quakers are holding a weekend seminar on prison reform from February 8 to 10 in Whanganui. They want to reduce imprisonment rates and influence Government policy.
The seminar is open to anyone. It costs $96, or more if people choose to live in. Attenders must register by February 1, and can find out more at www.quakersettlement.co.nz.