Key Points:

In John Key's six years in Parliament he has confronted several conscience votes - bills where MPs vote as individuals rather than as a party. Conscience votes are typically reserved for moral issues such as the drinking age, gambling, euthanasia, prostitution and homosexuality. MPs make up their own minds which way to go: a conscience voting record can therefore offer a window into what really makes an MP tick.

Examining the conscience votes Key has cast suggests he is conservative. But when that suggestion is put to him, he says: "I'm more liberal than my voting record."

Here's how he voted on the high-profile issues.

* Civil unions: AGAINST

* Prostitution reform: AGAINST

* Manukau City Council prostitution (prohibiting streetwalking and soliciting in public places): FOR

* Marriage amendment (defining marriage as between a man and a woman): AGAINST

* Death with dignity: FOR

* Sale of liquor amendment (raising drinking age to 20) : FOR

* Shop Trading Hours Act repeal (allowing territorial authorities to decide whether shops can open on Easter Sunday): FOR

One vote Key particularly wrestled with was the move to decriminalise prostitution in 2003. He voted for the highly contentious bill at its early readings and spoke in favour of it in a blunt speech in the House. It remains perhaps one of the only conscience vote speeches where he has strongly articulated his personal feeling.

Key said he supported the legislation "not because I wish to condone the actions of those who partake of this industry, but nor do I wish to condemn them. I believe that it is up to every individual to determine what fits within his or her definition of morality and values. I do not believe, and will never believe, that the Government can legislate for morality; that is for each and every individual."

Key's message to people fretting about the terrible impact the legislation would have was, "Get real".

"If this bill becomes law, I will not be skipping home to my lovely wife and telling her,'just before I came home tonight I popped into the local brothel, because it is legal now, honey'," he said.

Key even fired a shot in the direction of those lobbying him to oppose the bill - particularly those from religious backgrounds.

"The last thing I have to say is that I am not a terribly religious person, but I found it pretty hard to take when of the 220 letters and 123 emails I had, those who opposed the legislation came largely from the church. I simply look at the history of the church and the reasons behind the massive financial settlements for crimes that have taken place, and it looks a bit hypocritical to me."

Yet, despite his clear personal views, Key voted against the legislation at its final reading just three months later.

When asked what happened, Key explained first that his mother was very liberal and "I'm not miles away from it".

But the reason he changed his mind about prostitution was because some constituents visited his Helensville electorate office and suggested that supporting the bill would send the wrong signal.

A couple of the constituents had 16-year-old daughters. As parents, they felt that whether Key liked it or not, the bill would legitimise prostitution as a credible pathway for the girls.

Key said he started to think that in the end, he was a representative of these people.

He firmly believed that if he asked his electorate what they wanted, they'd want him to vote against it. "So I did. And that's always been the view I've taken."