People think that if you’re Prime Minister, you’re very powerful,” says Sir Michael Barber, who spent four years at the heart of government pushing ministers and civil servants to deliver Tony Blair’s priorities. “But when you’re inside No 10 looking out, it doesn’t feel so powerful. No 10 is small and the spending departments are very big. If you tried to do it all, you’d become a completely mad control freak.”

Few know as well as Sir Michael how frustrating government can be. In his book Instruction to Deliver, the former head of Mr Blair’s Delivery Unit gives a detailed account of life in what he calls the vortex.

“Around a Prime Minister there is a vortex, and the nearer you get to the centre of the vortex, the less space and time there is. The moment you step away, the space is filled, so no one notices you’ve gone. You have to have a strategy for being noticed or you will get marginalised.”

It is hard to imagine Sir Michael pushing himself forward. He is earnest, bespectacled, as befits a former professor of education. But he also exudes quiet determination This is, after all, a man who once walked across broken glass in his bare feet in front of 300 civil servants to demonstrate that “we will do anything to help you achieve”. There is just a hint of the cult leader about him. He describes a Prime Minister who is constantly distracted by other issues, is sometimes focused and sometimes not, and who won’t even make time for a five-minute premeeting. “If you were lucky, you might find yourself walking into the Cabinet Room with him, pressing a point, but even then it wasn’t clear whether you had hit home.” Yet Mr Blair was also a huge driving force with restless energy.

Sir Michael is relentlessly positive about the Government’s achievements on public services. But he also paints a picture of politicians and civil servants much more interested in the “what” and “why” of government than in “how” to achieve results. “There were loads of people who made government more complicated.”

Mr Blair took a long time to recognise this gap. “He said to me that ‘my second term felt like my first’. In the first term he would get things written, published, sometimes turned into legislation. Then he’d look again a year later and say ‘what’s changed, what has the public noticed?’.” In January 2003, for example, Mr Blair became alarmed about the rise in asylum applications. He went on News-night and promised to halve the number of asylum applications by September – a promise that was news to everyone, including Sir Michael. Had he just dreamt it up?

“You either have faith in the system (he clearly didn’t) or in his case you have faith that somehow you will be able to persuade the system to deliver.” This seems to have happened quite often: Blair would pull a lever, come back to find nothing had been done, and then fall back on his charm to force things through.

The two first met in 1995, and Sir Michael “was really struck by how open the agenda was. There were no old Labour shibboleths in the way.” Blair seemed to agree that the national curriculum, national testing and devolution of resources to schools – all Tory policies – were the way to go.

Sir Michael helped David Blunkett to develop the literacy and numeracy strategy for primary schools, the achievement of which he is rightly most proud. “Blunkett and Blair,” he says, “were one of the great combinations in modern politics.” Mr Blair wanted a set of schools that appealed to people who could afford to go private, Mr Blunkett wanted to deal with discipline.The two were also afraid that the middle class might opt out of state schools and the NHS unless provision improved. If too many went private, it could become impossible to keep taxes high enough to guarantee decent standards for everyone. “Blair saw quite early on that public services were a fundamental contributor to a good society,” Sir Michael says. In doing so, he “achieved a settlement as profound and lasting as Attlee’s”.

One of Sir Michael’s strengths is clearly his optimism but he sometimes seems to view the world through rosy spectacles. On the other hand, this is a man who saw how hard it was to get things done. In his book he describes how when unpacking his new office he finds that someone had lovingly prepared a box containing one saucer and six teaspoons. He reflects drily that this is what parts of the Civil Service might consider a job well done.

When Lord Turnbull, the Cabinet Secretary who described Gordon Brown as “Stalinist”, agreed with Sir Michael that a revolution was needed, but hoped for one by stealth, Sir Michael felt that it was a contradiction in terms. “Remember the rage and frustration,” he kept telling his staff, “because that will make you an agent of change.”

Sir Michael refuses to be drawn on Brown, other than to say that he was always supportive. “Gordon is usually associated with the economy, but he also did a great deal for public services.” Which is irritatingly discreet.

Sir Michael’s maxim, which I suspect he repeated ad infinitum to weary troops, was “gentle pressure, relentlessly applied”. It is a shame that he is not still in government to keep it up.

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