This column tries to resist conspiracy theory. All the same I couldn't help wondering why the 'Constitutional Declaration' that Tony Blair and a very happy Paddy Ashdown signed last week had been timed to coincide with Gordon Brown's big public spending statement, which put it in the shade.

Government officials denied a plot, but couldn't help saying how decent it was of Tony to be so nice to Paddy on constitutional reform when his party was still spouting its 'economically illiterate' attacks on the prime minister's key policies.

In such ungracious circumstances it seems a good opportunity to be nice to the Lib Dems, who devoted an earlier chunk of the week to making the kind of lateral policy link New Labour prides itself on: the fact that money invested in home insulation for poor people and elderly people would be money saved to the NHS in preventive healthcare terms.

It is certainly true that what the chancellor announced has enormous implications for the way public expenditure is managed in this country and, potentially, for the NHS and its patients. He wants to be financially prudent. Indeed, he mentioned Prudence so often that my colleague, Simon Hoggart, wondered if she was his girlfriend.

But he also wants to deliver Labour's promise of better public services, education, health and (newly promoted?) transport, both in terms of cash to run these services and - vital to the NHS - the capital sums needed to restore and replace neglected hospitals and equipment. As even the Financial Times noted, it has always been ridiculous that post-war Treasury rules meant that 'investment is the first casualty in any squeeze on spending'.

That may help explain, incidentally, why the public infrastructure across the Channel - those trains, roads and Stades de France on TV display during the World Cup - looks so much better than ours: it has long been a public/private failure in Britain (hence the Channel Tunnel shambles), and Gordon Brown is determined to put it right. Frank Dobson can only be a beneficiary, provided he keeps up the downward pressure on costs and inefficiency, as measured by health outputs.

But the confusion of media headlines (did the spending pledges matter more than the sale of public assets?) may continue to unsettle markets and force up interest rates. That will not help the NHS or the mortgage payments of Rodney Bickerstaffe's Unison members. Remember, it all depends on continued economic growth, which we may not get, whether or not that Asian crisis infects us too.

And if Iron Gordon's plans go as he says, they will double net public investment, but only to 1.5 per cent of gross domestic product. They will raise public spending by 2.5 per cent (which would average out at less than the Tory average on election day - 1.5 compared to 1.8 per cent - the Lib Dems unkindly pointed out). And, asked Ken Livingstone, will he keep his nerve to that level if we get a recession?

Back in real life, it sounded more like business as usual when the Lib Dems launched a Commons debate to demand a 15-year programme to insulate 1.5 million homes. Peter Brand, MP for the Isle of Wight, made the call, backed by assorted Lib Dem and Labour MPs.

For me, the best statistic came from Truro's Matthew Taylor. Between 30,000 and 60,000 premature deaths occur each year (ministers admit the lower figure) because of the cold, and extra hospital admissions cost Mr Dobson pounds1bn a year. Deaths rise by 14 per cent in Sweden each winter, 10 per cent in almost-as-cold Norway, but 14 per cent in mild-but-damp Britain, he revealed. Angela Eagle, the junior environment minister, rather than Tessa Jowell, answered the Lib Dems. Yes, ministers know all about fuel poverty, she said. But energy-efficient homes may not be the answer for the really poor: what they need is money to pay for fuel. Labour is on the case, struggling to make up for Tory 'years of under-investment'. Over to Iron Gordon. Yet again.