Dressed in a starched, light blue Rodd & Gunn shirt and crisply pressed, dark khaki chinos, John Key is the very model of the modern business executive sacrificing his Saturday at home to make headway on mounting paperwork at the office.

Image matters. The Prime Minister's staff are using Key's rare presence in Wellington on a weekend to schedule media interviews marking National's first year in office. You get the feeling, however, that Key would be garbed in smart casual attire regardless of his afternoon appointments with journalists and photographers.

It is a non-threatening, corporate uniform which makes Key look conventional, mainstream and just one of a crowd - attributes which seem to help him quickly get on the same wavelength as his audience, regardless of its makeup.

Key's sheer ordinariness has fooled opponents into making first impression assumptions that there is little substance behind the confident, smiley face he presents to the world.

Key would not claim to be an intellectual. But he is very bright. Those who have worked closely with him speak of a capacity to absorb mountains of information and a laser-like capacity to focus on what needs to be done.

He is anything but ordinary. The chief executive of New Zealand Incorporated is nothing short of a political phenomenon.

As one Beehive operative of long experience puts it, Key is rewriting the rules of New Zealand politics. That is a sweeping statement. But it goes some way to explaining why public support for National - confirmed in today's Herald-DigiPoll survey - has climbed to unprecedented highs for a ruling party in its first year of government and, just as crucially, continues to remain at that level.

Key cites his Government's fulfillment of manifesto commitments and steering the country through and (he hopes) out of economic recession as crucial in consolidating support for his party. Cabinet ministers readily acknowledge, however, that National's post-election dream run is overwhelmingly down to Key's strong rapport with voters - especially females who shunned National in the past.

Labour Party insiders grudgingly agree, but with a subtle twist in the language: National's popularity rests on Key's popularity. When the latter starts to fade, the former will quickly evaporate.

Or so Labour prays. Labour, however, has made a bad habit of underestimating Key.

One of the principal ways he is seen to be rewriting the rules is by applying a "will it work" test to policy proposals rather than first asking whether they sit comfortably with National Party ideology. Key's willingness to search for ideas outside conventional boundaries is in tune with an electorate less hung-up about ideology than in the 1980s and 1990s.

This may irk some colleagues who see the vast gap between National and Labour in the polls as a rare chance for National to adopt a more radical and right-leaning prescription.

Indeed, indications of such an agenda have seeped into the public arena, notably in the form of potential mining of Conservation Department land and the privatisation of ACC.

Key seems to have no difficulty with either proposition. However, he is extremely wary of breaching National's 2008 manifesto. He believes it is vital that voters feel confident they can trust National in government.

In that regard, Key has been helped by Labour painting him as a wolf in sheep's clothing before the last election. The public has thus been pleasantly surprised to discover that is not the case.

Key keeps very close tabs on National's private polling. He can and does put the kybosh on anything he feels may vex voters unnecessarily. His returning National to the Government benches and its subsequent gravity-defying jump in the polls mean one thing: whatever Key wants happens - full stop.

Add to Key's centrist inclinations another Cabinet dynamic - Steven Joyce, Key's closest confidant, is said to likewise argue that National drive strictly down the centre-line.

One Government source says Key and Joyce believe a government can get away with doing one or even two things which seriously annoy voters. "By the third, you are in trouble."

Asked if such pragmatism annoys some in his party, Key laughs and replies: "Hell yes. Of course there will be some who think I am too much to the centre of politics and not ideologically-driven. I would argue very strongly that I have some very clear values and principles that drive me. I think they are closely aligned to the values and principles under which the National Party was established. And they are about equity, fairness and predictability."

Most Labour MPs would have little difficulty being guided by such principles, which underpinned the welfare state of the 1950s and 1960s and helped Key to become the state house kid who made good.

Key's pragmatism, however, also marks a generational shift in New Zealand politics. Peter Dunne has remarked that the highly-talented 2008 intake of new MPs "reflect today's instant world, where decisions are made quickly and decisively, based on a combination of intuition and diverse experiences, and often on a no-regrets basis where it is no big deal to admit things did not work out as intended and have to be changed, and then just move on without recrimination to the next issue.".

That is Key in a nutshell. Dunne also noted that "references to what happened in the 1990s, let alone what side one was on during the Springbok Tour or, heaven forbid, the Vietnam War are utterly irrelevant to the values of this new generation, as Helen Clark found out dramatically last year, and Phil Goff is continuing to find out".

Unlike Goff, who must reinvent himself, Key had the considerable advantage of not carrying any political baggage from a past Government into the Prime Minister's office.

Though Goff is an effective communicator, Key operates on another level. Unlike some politicians, he never talks down to people. He instead likes to disarm his audiences - no matter how big or small - by kicking off proceedings with a witty anecdote. More often than not, the joke is at his own expense. And deliberately so. The self-deprecation helps to break the ice.

A typical example was a recent meeting with youngsters at a riding school. Praising their ambition to represent New Zealand in show-jumping at the 2016 Olympics. Key turned to their proud parents, telling them "and you'll be able to watch it all on Maori television".

It is this willingness to make light of mistakes that seems to go down well with voters. Fallibility has become a political strength. But for how much longer is a moot point, especially when it comes to day-to-day political management and co-ordination between National and its support partners - Act, the Maori Party and Dunne's United Future.

"If you want perfection, then politics is the wrong place to look," Key says in answer to charges of sloppy political management. "Politics is dynamic ... you are dealing with support parties who have different objectives from the main party and sometimes they want a debate in public because they need to engage with their supporters."

Key is not the control freak Clark was. He seems to be allowing third parties more leeway to express disagreement with National and more space to blow their trumpets when they secure policy trophies.

Given National's shortage of available partners, the survival of its current ones is essential. Maintaining National's fruitful relationship with the Maori Party is of paramount priority for Key. That will hinge on the Maori Party getting satisfaction on the foreshore and seabed and, perhaps even more crucially, the devolving to iwi of the funding and provision of social services for Maori.

In comparison, the unseemly squabble over screening rights for the 2011 Rugby World Cup is relatively peripheral.

However, some sources suggest the handling of that stoush should ring alarm bells over the apparent lack of overall managerial oversight when it comes to negotiations with partners.

There is amazement that Nick Smith was allowed to say accident compensation legislation was ready to go before Parliament when not only did he not have the numbers to pass it, he had also had similar difficulty getting the numbers for his bill on emissions trading just weeks before.

In part, such shambles are the result of Key's more hands-off style which allows Cabinet colleagues more freedom in how they run their portfolios. It is another example of how Key is doing things differently. But it comes with strings attached. Key expects results and is monitoring the progress of ministers in meeting performance targets. He says he will be speaking to one or two about their performance so far. Not surprisingly, he declines to name them.

Key is quite capable of giving wayward ministers a bollocking, if required. But visible displays of anger on Key's part are rarely seen, even if he exasperated by a colleague's behaviour.

He has blundered himself, notably the appointment of the polarising Christine Rankin to the Families Commission. Key's usually sharp political nous deserted him on that occasion.

There have been the big calls - the refusal to act on the result of the smacking referendum and sending the SAS back to Afghanistan. Yet, a year on from the election, it is still difficult to discern the direction in which the Government is going. Presumably it knows, because it is a very busy Government. It would be useful if it told the rest of us.

If Key has a major flaw, it is in not drawing the big picture often enough.

Key's power is at its zenith. But how does he intend to use it? What legacy does he want to leave? The next 12 months will be true measure of his prime ministership, judged on what is done to get his promised "step change"in New Zealand's economic growth.

Voters' memories are short. Failure to deliver on the economy could see Key's sparkling performance in his first year count for nothing more than burnt-out neon come the 2011 election.