"Many days I was depressed by the dark side of human behaviour.
"But other times I was inspired by the resilience of victims, and sometimes by previous offenders who were gradually putting their lives back together."
One case would stay with him forever, however.
"One morning, outside a Tauranga school, a guy called Tony Robertson, who already had a string of convictions, managed to convince a 5-year-old girl to get in a car with him.
"He pretended to talk to her mum on the phone, and promised the girl Christmas presents.
"Thank God, her brother, who was seven, went in to school and told the teachers what had just happened. They called the Police."
Immediately, Police organised a district-wide manhunt. One officer – Sergeant Dave Thompson - had had a hunch on where such an offender might go and he drove out of town to Kaiate Falls.
"There he found Robertson and the girl still in his car, crying. To this day, I believe Sergeant Thompson saved her life, " Bridges said.
"For me, my job was to prosecute Robertson. I tried to get him the strongest sentence New Zealand has, which is preventive detention. It means a person can be kept in prison their whole life.
"Instead he was given seven and a half years in jail, and was let out in December 2013 because he'd done his time."
Less than six months later, he had abducted a woman but that time there was no heroic police officer to save her.
Her name was Blessie Gotingco and Robertson raped and murdered her, Bridges said. After that, he got preventive detention.
"I'm sorry to relate to you such an upsetting case but it's one reason why, as Leader of the Opposition, one of my priorities is law and order.
"I don't apologise for that. The lives of New Zealanders depend on it.
"I believe in most people getting another chance, and I am a strong believer in rehabilitation to help people move away from a life of desperation and crime.
"But I also believe that jail is absolutely the right place for some offenders.
"It bothers me that the Government is talking about lowering the prison population, without explaining how it will lower the crime rate first."
There were lighter moments in the speech. He talked about auditioning for the role of Oliver is the school production of the musical, but instead was given the role of the undertaker.
He talked about meeting his future wife, Natalie, at Oxford and how he ordered black coffee to impress her instead of his preferred milky blend – and then spilling it over himself.
He talked about his time at the college – where he was head boy in 1994 – and said because he was asking for their vote they should know what drove him.
"I grew up a Westie – one with a blended background. My mum is Pakeha and Dad is Māori.
"We lived near enough to here that I walked to school. As a family, we weren't well off, but we never went without."
He is the youngest of six children.
"Looking back at my time here at Rutherford College, I was a bit of a swot.
"I had some fantastic teachers who taught me that ideas matter.
"Although when I was keen to talk about them – which was most of the time – I think my teachers thought maybe they'd made a mistake in encouraging me. A few of them thought I was pretty cheeky.
"I'd often find myself getting into what I'd call 'robust debates' with teachers in class. I think they just called it arguing.
So, no surprise, I got into debating. It's a useful job skill for politics - although I can safely say Mum no longer writes my debate notes out for me on those little cards."
He talked about life after leaving school: "If you know what you want to do, that's great. If you don't yet have a clue, that's fine too.
"When you're young, it can seem like everyone else knows more about how the world works, and where they fit in. Believe me, most of the time, that's not the case.
"But not knowing what to do with your life is not an excuse for not working hard to better yourself."
Not knowing what you want to do was all the more reason to stick at education or training, or following their passion "because you need to be in a position to grab opportunities when they come up."
"Most importantly, do something. Statistically, life outcomes are poor for people who sit around and do nothing.
"Unless you win Lotto - and sorry to break it to you, but the chances are you won't - success is always going to involve hard work.
"Naturally, our start in life influences who we grow up to be.
"But even those who have tough childhoods do not need to be defined or limited by that. All of us have the ability to better ourselves, and improve our lot in life. "
