As a high-ranking magistrate at the justice ministry in Paris, Eric Alt has witnessed a decade of corruption scandals in French politics. So it was with a seasoned eye and a wry smile that he considered the nascent debate on party funding in Britain. "William Hague?" he said. "He'd probably be under investigation and facing trial if French law applied." Stuart Wheeler, the chairman of the betting firm IG Index, who gave £5m to the Tories, would be in a similar mess - caught, like Hague, by the F50,000 ceiling on giving or receiving political donations. So, too, would Lord Sainsbury, as a result of his £2m gift to Labour.
As for Tony Blair, he would be looking at a ten-year jail term if a connection was found between Bernie Ecclestone's £1m gift to Labour in 1997 and the government's decision to exempt his Formula One races from a ban on tobacco advertising. Under French law, the offence is trafic d'influence - favouritism. "It would have to be proved first that Blair knew about the money, and second that there was a link," said Alt. "But for a determined investigating magistrate, that would be within the realms of the possible."
Could it happen here? Since February, British law limits party spending to £19.77m in the year preceding a general election, and demands publication of the names of all donors who give more than £5,000. An electoral commission has been set up to oversee campaign expenditure.
Britain is not France. Tax evasion is considered a misdemeanour, not a sport, and a red light means stop, not accelerate. We can hope that our politicians reflect this culture. But from his small office overlooking the Place Vendome in central Paris, Alt is sceptical. "When the 'clean hands' operation began in Italy, we thought we were far more honest in France, and that nothing like that could happen here. Now we know that the pressure on politicians produced similar behaviour in both countries. The only difference is that Italian magistrates had the means and the autonomy to get to the bottom of it all in Italy."
In France, they are still digging. A new generation of investigating magistrates, such as Renaud van Ruymbeke and Eva Joly, has begun to piece together the system used by virtually all political parties to shore up their finances. This involves a systematic request for donations, often via intermediaries, from companies bidding for public-works contracts. In 1996, Henri Emmanuelli, the Socialist Party treasurer who organised just such a network, got an 18-month suspended jail sentence; he now faces new allegations that supermarkets had to pay for planning permission. Jacques Chirac's Gaullist party is also under scrutiny amid claims that it extorted huge sums from firms in Paris in the 1990s.
As the scandals have emerged over the past ten years, so legislation has been steadily tightened, following the first, timid law introduced in 1988. Since 1995, there has been a ban on all donations from companies or trade unions.
Is the same thing possible in Britain? There is no suggestion that Wheeler was looking for anything from the Tories in return for his £5m. Or that McDonald's, Tesco, Pfizer, British Aerospace or any of the other firms that have made donations to Labour were seeking to benefit. But then again, no one would have suggested such an idea in France in 1988 - at least not publicly.
The first electoral funding law was seen as a broad framework, not as a weapon in an attack on the political establishment. In fact, it was not the legislation that mattered, but the ensuing attempts to break it, with oil company funds being moved secretly into party coffers from Switzerland and Africa, and government advisers bringing black briefcases full of used banknotes from abroad.
As investigators delved, they discovered more malpractice. Public indignation led to new laws to clamp down on it and that, in turn, created new forms of malpractice. The results are astonishing. For example, at least 17 French mayors who stood in the local elections in March had been found guilty of, or charged with, corruption offences.
Few would have had any judicial difficulties in Britain. Unlike the French, we do not see a £5m donation as a criminal offence, since there is no ceiling on donations. Nor do we condemn monetary gifts from sectors such as communications and public utilities, which depend upon the authorities for their profits.
In France, in almost every instance, it has been investigating magistrates who have discovered corruption. The French electoral commission, set up to keep an eye on campaign spending, has not, according to Alt, discovered a thing. "It does not have the means to penetrate the financial complexities involved in corruption," he says. By coincidence, no doubt, the British electoral commission seems to have been modelled on its French counterpart.
Alt does not believe that France has got anywhere near to cleaning up its political system. "It is very easy," he says, "for the interior ministry to decide that a magistrate overseeing a sensitive and difficult inquiry should have only a couple of police officers to help them. Many, many affairs have been suppressed in this way.
"An inquiry is launched only when a crime is reported, and that is usually by the victim. But it is in the nature of corruption that the only victim is the taxpayer, who does not know. Most of the cases in France have come to the attention of the judges because of aggrieved mistresses, disputes between friends, or particularly rows within parties - when someone has gone and lifted the lid on fraud. If parties stay united and politicians remain on good terms with their mistresses, it's difficult to get anywhere in this sort of area. We are certainly not a model for you to follow."
Not a model, perhaps, but a worrying example for British politicians to contemplate. Chirac, for example, will probably face two criminal inquiries when he loses his presidential immunity, both resulting from inquiries into his party's finances. Francois Mitterrand would almost certainly be in the same boat if he had not died in 1996.
Comparisons between Blair and Hague on the one hand, and Chirac and Mitterrand on the other, would be defamatory and unwarranted - for the time being. "I do not want to suggest that British politics has the same flaws as French politics," said Alt. "But we have seen over the past decade that the same causes tend to produce the same effects in different countries. And in politics, the causes tend to be the same."