It is not difficult to imagine Kenneth Clarke circa 1750. He already has the claret-filled shape of an 18th century political hack; and, with the simplest addition of a lop-sided wig, could easily be painted into Hogarth's hustings - leering down from the rickety platform and bellowing to the mob below that ancient pledge, once so central to British political life: Cheap Beer!
Well, those days are back; for that, in essence, is what Mr Clarke must say on Tuesday if his party is to stand the faintest chance of victory at the next election. Of course, he will not literally offer us cheap beer. Indeed, I rather suspect Treasury pressure will prevent him from reducing the duties on alcoholic beverages by more than a penny or two. No, Tuesday's equivalent of "cheap beer!" will be "tax cuts!" The only mystery remaining is the form that these will take.
Nothing new in this, you may say. Aren't we all too used to Tory Chancellors manipulating the "electoral business cycle" to their party's advantage with cynically timed cuts in direct taxation? Well, yes. But in the past the Opposition has invariably denounced them for doing so. This time it will be different. For on Tuesday, there will be another, equally bulky, equally 18th-century figure waiting on the other side of the dispatch box - and ready to match Mr Clarke tax cut for tax cut.
Gordon Brown is in some ways an even more Hogarthian figure than Ken Clarke. There was, after all, no more familiar figure in the seedy politics of the 18th-century than The Hard-Nosed Scotsman On The Make. Down they poured to London after the Act of Union, intent on carving out careers for themselves. And today, under the banner of new Labour, they pour down harder than ever.
For weeks, Mr Brown has been preparing the ground for what promises to be one of the most outrageous budget replies in the Labour Party's history. He has already flown an unusually large number of pre-Budget kites, including a windfall tax on privatised utilities and workfare for what used to be called "the undeserving poor". But the kite that flew highest was his audacious proposal for a 10p in the pound bottom rate for income tax. That gives us a good indication of what Mr Brown will say on Tuesday; the moment the Chancellor slumps back on the Government front bench, Big Gordon will be on his feet ready to lead his own mob in a triumphant chorus of - "Free Beer!"
And when Mr Brown sits down, having made his breathtaking bid to undercut the Tories at their own game of electoral bribery, the implication will be clear. After some 200years in which ideology has called the tune, the British left has at last returned, snout-first, to the politics of the pork barrel.
Of course, you do not have to go as far back as the 18th century to encounter this sort of thing. You only need to look at the way takeover bids are conducted in modern business. The predator takes out full-page advertisements to rubbish the existing management and to offer shareholders mouth-watering bonuses and future dividends. With glossy mailshots, the management responds in kind: the bidders are, in truth, mere asset-strippers, etc. On Tuesday, Mr Clarke and Mr Brown will be performing a version of the same corporate ritual. In the language of the City pages: "New Labour launches hostile bid for UK plc."
All of which is very shocking and deplorable, no doubt. How shameful that the House of Commons - once the scene of great political battles for religious toleration, constitutional reform, individual liberty and social equality - should sink to this level of a political stock exchange.
But is it so terrible? I am actually rather delighted by Mr Brown's conversion to pork-barrel politics - although I fear it greatly increases his party's chances of winning the next election. For it means that, for the time being at least, the old ideologies that dominated the period 1789-1989 are finished and done with. Quite simply, there is no longer any point in trying to run election campaigns in the name of Liberty, Equality, Fraternity or any of the other catchphrases from the 200-year Age of Revolutions. "Rights" are out. "Interests" - plain old money-grubbing material interests - are back in.
The reason for this is simply that a consensus has been reached on all the main issues raised after 1789. The right has portrayed the result of the Cold War as a victory; but if you regard the war between conservatives and progressives as dating back to 1789, then the result has been more like a draw. In accepting democracy, conservatives have accepted an enormous shift towards redistribution of income: in abandoning socialism, progressives have given up on the idea of forcible redistribution of wealth.
With the welfare state fundamentally intact in spite of more than 15 years of Tory government, but with Labour converted to the limits imposed on it by Thatcherism, the consensus is clear: government takes about 40 per cent of GNP in taxation, the bulk of which it redistributes through the social security, health and education departments, leaving a little left over for its old functions - defence, law and order and the national debt.
The only problem is the very old-fashioned way UK plc is run. Every adult citizen is a shareholder with voting rights which are delegated every few years to a huge and weak advisory board of MPs. Even more oddly, we pay our management the worst rates in the world (especially the poor old Chief Executive in 10 Downing Street). And the accounts of the firm are expressed in an anachronistic language which no serious businessmen would put up with. If you discussed the affairs of a major corporation in the way the Chancellor will discuss those of UK plc tomorrow, the most docile shareholders would revolt.
So my advice to Mr Brown is this. Go for pork-barrel politics by all means. But go forwards instead of backwards for inspiration. Instead of the style of William Hogarth, adopt the style of Michael Milken - and turn the next general election into the mother of leveraged buyouts.