If David Cameron struts centre-stage as this Government's drama continues, Francis Maude is the man perched behind the scenery with the cable cutter, sprocket remover and box end wrench. His job is to make sure that while the show carries on the lights don't go out.  As Paymaster-General, his Cabinet Office responsibilities include quangoes (culling them), strikes (stopping them), the Big Society (making it happen), and Whitehall costs (keeping them down).  And here he is, in a rather ungrand office with a very grand view of Horseguards Parade.  There is a transient feel to the set-up: no family photos, papers strewn over a large desk - it fills perhaps a quarter of the room - a laptop set on a corner table.

We begin by asking him how his talks with the unions went the previous morning.  His eyes chill to the colour of an ice floe beneath an Arctic sky: "How did you know about them?" he probes, perhaps suspecting a conspiracy between ConservativeHome and the Public and Commercial Services Union.  We point out that they were reported in the papers.  Maude relaxes very slightly, before going on to explaining that "We don’t particularly draw attention to the discussions with the unions that have taken place, in a very constructive spirit, and we’re hoping to make progress".  This is clearly the moment at which to remind the Minister that Boris Johnson has described the Government's stance on the unions as "lily-livered".

"Yeah, and it's an argument which others have made, the CBI’s made the same case, and we certainly haven’t ruled out, in due time, making changes. But at the moment we think the trade union laws don’t work badly, and we will constantly keep them under review."  Which, Maude confirms, is a way of saying that "we're not persuaded that there's a case for change at this time".  The casual "yeah", followed by a cautious answer, is a bit of a verbal tic, and a reminder of the paradoxes of Maude.  The arch-moderniser is an old-style Tory, at least by background: his father was Angus Maude, once Party Chairman.  A member of a Euro-sceptic dining group when I was in the Commons, his signature is on the Maastricht Treaty.

While the thoroughly modern Ministers of the new generation set out to charm, Maude has the directness of an older generation of Conservatives: whether one warms to him or not, he looks like a Minister.  How does he feel when he reads that the Big Society is on its fourth relaunch?  "It's about as pointless a thing to write as when William Hague makes a speech about foreign policy, and people say or don’t say that this is the 27th relaunch of our foreign policy."  So it's all the media's fault?  "No, it's not your fault at all.  You’ve got to write something. But when Michael Gove makes a speech about educational reform, he’s not re-launching the educational reform plans, he’s talking about them and developing the ideas."

But Gove isn't being criticised for re-working a policy which, to say the least, hasn't yet captured the public imagination.  "Well all I’d say is that I absolutely undertake that we will be re-launching it this week, next week, the week after, probably several times a week, and if you want to keep a tally of the number of re-launches we’ll be well into three figures by the end of this year because we will talk about it all the time...I’m fairly relaxed about what people write about it, actually, because the truth is that people have some sort of broad understanding of what society is...a bigger stronger society is one where more people do more things with each other, for each other, in their communities, for their communities."

Is he keen for the private sector to have a bigger role in a Big Society, to manage more public services? Maude doesn't exactly seize the idea.  "There used to be a sort of binary choice between services being provided in house by big, monolithic public sector organisations versus for-profit, fully-commercial, fully-outsourced provision. I think the world we’re now in there’s a far more interesting, sophisticated array of potential providers."  He cites the delivery of the Work Programme, of which over a third will be provided by the voluntary, charitable and social enterprise sectors, although he later confirms that "there’s absolutely a role, and a growing role, for the private sector in delivering public sector change".

Maude is also legendarily enthusiastic about mutuals - some for profit, some not so.  Maude quotes the academic Julian Le Grand, who's chairing a Government taskforce on mutuals, as asking whether a million of the public sector's six million-strong workforce could be in mutuals in five year's time, but "this isn’t something we can drive because it has to be pulled by the staff to make it happen".  We ask when the Public Sector Reform White Paper will be published, and if it's really necessary.  "When? I don’t know when.  There’s a huge amount of work and, partly because of the second question, which is that there’s a lot of work going on anyway."

Asked if the merging of much of Number Ten and the Cabinet Office has led to the creation of a Prime Minister's Office, Maude streses that "The Cabinet Office has always said that one of its primary roles is to support the Prime Minister...we support the Prime Minister, the Deputy Prime Minister and house both."  He argues that government needs a "loose-tight" balance: more control of essentials at the centre - "strategy, communications, cash, headcount, human resources, operating standards, big projects" - and more devolution of nearly everything else away from it.  He says that advertising spend has contracted by 80 per cent, that £800 million has been saved from suppliers, that he probes the case for every spending item above £5 million personally.

Maude's tieless attire was exploited by Tony Blair to mock the modernising Tories - branding them as "tieless, shoeless and clueless".  (Maude is wearing a blue-and-brown striped shirt, dark trousers, a dark blue V-necked sweater, and black shoes...but no tie.)  He's been reported to believe that if the Party wins an outright majority at the next election, it should reform the coalition with the Liberal Democrats none the less - a view recently claimed to be that of "friends of Cameron".  Maude looks alarmed at the suggestion.  "No, I haven’t said that. I’ve never said that. Our aim will be to win an outright majority at the election and it’s really hard to see how you form a coalition in those circumstances."

"I have heard people argue this case is all I said. In reality I think it would be very difficult to achieve. The dynamics would be so different. But I would also say for clarity that it has been a huge advantage for the country that in the circumstances of having to undertake emergency fiscal surgery there’s been a broad-based government commanding a broad consensus of opinion."  But has David Cameron brought to fruition the work that he and Michael Portillo started?  "I think David understood from the outset that the Party has only been as successful as it has been over the centuries by modernising itself...the way I tend to put is that modernisation is one of the strongest traditions in the Conservative Party."

A last question.  Maude was first a Minister under Mrs Thatcher.  He first entered the Commons the best part of 30 years ago.  He has the knowing, sardonic, faintly melancholy look in his eye which suggests a man who's seen it all before - who knows well how fragile the stageshow of government really is.  Is he enjoying himself?  Maude laughs.  "You delicately make the point that I’ve been around for a bloody long time and I’m very old but I think it’s fair to point out that I also did get into politics extremely young. I was in Parliament just before I was 30, entirely by accident."  (It is very old Tory to say that rising in politics is a matter of happenstance.)

"Almost buried in your question is the suggestion that I’m a bit cynical about it all and that is absolutely not the case.  Absolutely not the case. I think we’re at an extraordinary moment where, in terms of public services and what I do really is all about how government works and how do we make it work effectively, how do we, in this incredibly demanding period of fiscal retrenchment, also drive change that meets peoples’ expectations in terms of the quality of public services...not uniformly, because life isn’t uniform and progress isn’t uniform.If you try to make progress uniform then you slow it, because actually you slow it to the rate of the slowest ship in the convoy. So you need to allow for differential progress, which there always will be."