As the state of the nation’s finances rapidly worsens, the Conservatives have repeatedly pinned the blame on Gordon Brown allowing government borrowing to spiral ever higher, even in the economy’s boom times. “He didn’t mend the roof while the sun was shining,” in the soundbite that George Osborne, the Shadow Chancellor, and David Cameron have made their mantra. They are wholly right.

The news that the Treasury is working on an overhaul of the strict rules for the public finances that Mr Brown put in place as Chancellor is predictable. The scale of the deterioration in the Treasury’s books meant that the rules were inevitably going to be broken in the next few years, confronting Mr Brown and Alistair Darling with an embarrassing political headache.

The Government will therefore put the best face possible on a recasting of this regime, and try to pin as much of the blame as possible on the deepening economic downturn. Yet a rejig of the rules is roughly equivalent to sticking a plastic bag over the hole in the roof that Messrs Cameron and Osborne so often remind us about.

The planned overhaul of the Treasury’s financial regime will give the Chancellor some more leeway to let borrowing rise as the state of the economy worsens. To that extent, at least, it is sensible. Trying to curb the spillage of red ink across the books at present would mean reining in spending or raising tax _ and there could not be a worse time to do that. Such action would only aggravate the plight of the economy.

Yet in the longer term, whatever is down to the rules does little to alter the bigger picture that the government’s finances are in a mess, and a bad one at that. Borrowing consistently rose to levels higher than intended during Mr Brown’s time in Number 11, and has continued to do so since Alistair Darling’s arrival. The Government spent more than it raised year after year, and kept the spending spigot wide open even as taxes fell short of its hopes. So it slid deep into the red, and is now sliding still deeper.

It now seems unavoidable that borrowing will head towards £60 billion a year or more in the next few years, and that Mr Brown’s 40 per cent of GDP ceiling for the national debt will be decisively broken. That extra cash will help to shore-up economic growth in the short term. In the longer run, though, sky-high state borrowing now can only mean higher taxes, and maybe also spending curbs after the next election. Which will be as bad news for Messrs Cameron and Osborne, should they take office, as it will be for Labour if it clings to power.

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