This Autumn Statement was always going to be a difficult outing for our new Chancellor of the Exchequer, Spreadsheet Phil. He's on record as warning that our level of debt is 'eye-wateringly' high. Meanwhile the economic outlook is uncertain, following the Brexit vote. And to make matters worse, there's a black hole in the budget figures, according to the Institute for Fiscal Studies. Hardly an encouraging background for any Minister making his first big set-piece speech.

Yet for a few exhilarating moments it seemed as though Mr Hammond was about to brush all those concerns aside. We're the fastest growing major economy in the entire world, he cried, to Tory cheers. It has 'confounded commentators with its strength and resilience,' he went on. In fact he seemed so relaxed that he even ventured a joke or two – quite a departure for a chap with the reputation of being a bit of a dull dog.

And what a change it made from the dire prophecies of his predecessor, only six months ago. Remember George Osborne's warnings of the terrible things that would happen if Britain voted to leave the EU? There would have to be an emergency budget, he told us. An extra 2p would be slapped on income tax. There would be savage rises in fuel duties, slashing cuts to the NHS, fewer police and lower pensions.

Well that all proved to be a load of hysterical, alarmist rubbish, didn't it? None of those things happened at the time and neither have they happened now. Indeed Hammond froze fuel duty, while handing out some modest giveaways to the so-called JAMS – people who are just about managing.

And so the proposed cuts in Universal Credit will be eased somewhat, to help the worst-off in society. There will be curbs on rip-off letting agencies, to help people who rent their own homes. More money will be spend to encourage housebuilding. The National Living Wage will go up next year, as planned. And on top of that there will extra spending to improve transport and encourage productivity.

But let's not get carried away. The outstanding features of this Autumn Statement are not these spending commitments, which are very modest indeed, but the huge sums which the Government is borrowing and which it will continue to borrow for years to come. We're awash in a sea of debt. And all that stands between us and drowning are Hammond's promises of new fiscal rules.

Ah, yes. Fiscal Rules. Gordon Brown had them when he was Chancellor and we ended up with the great financial crash of 2008. In fact, successive Chancellors have established no fewer than 12 sets of fiscal rules since 1997. And you'd need all your fingers and both your thumbs to count how many of them have been broken.

According to the Office for Budget Responsibility, the sorry truth is that we're borrowing more than ever. We were expected to borrow £55bn this year, for example. In fact we'll be borrowing 68bn. Next year we were expected a borrowing figure of £39bn. In fact it will end up at £59bn.

On and on it goes. And according to forecasts from the OBR the situation won't be improving any time soon, because growth is likely to slow down for the next two or three years and won't return to anything like the current level until 2020. That, of course, means lower tax receipts and therefore compels us to sink deeper into the red.

And so we're no longer planning to achieve a budget surplus by the end of this Parliament. Instead Hammond promises that the Government will achieve a balanced budget 'as early as possible', a phrase so vague that it can mean anything or nothing.

Well, in one respect we're fortunate, since interest-rates are currently very low, which makes it cheaper to borrow. But how long that will last, if inflation rises next year, as expected? And how great will the temptation be to borrow just a little more, when the spending demands are so great, on everything from the NHS to the crisis in our prisons?

The plain fact is that we can't go on living beyond our means, borrowing and borrowing our way out of every difficulty. Sooner or later our indebtedness will become unsustainable – and what then? Remember that Britain's pound is no longer an international reserve currency. We can't rely on the money markets to go on bailing us out indefinitely. Sooner or later we'll run into a brick wall. But by then, of course, it will be too late.

Hammond may have made the best of a bad job. Certainly most Tory MPs seemed to like what they heard. But the level of our debt is still eye-wateringly high. And one day, if we're not careful, it may overwhelm us.

Michael Toner is a former Fleet Street political editor and co-author of a series of Bluffers' Guides on Europe.