Why, for the first time in my life, I won't vote Tory next week . . .
Traditionally, I am a Tory. Once in the polling booth it is never hard for me to put my cross beside the name of the Conservative candidate.
I've stayed loyal even during times when the Party has been in deep political trouble.
In fact, I've taken a special pleasure in supporting the Conservatives at those general elections, such as in 2001 when there was a Labour landslide, when it was deeply unfashionable to do so.
And yet now, with the Tories seemingly certain to win the next general election, I have a problem.
Not with next Thursday's local elections, in which those Tory candidates standing for council posts are, for the most part, decent men and women untainted by Westminster sleaze, but with the simultaneous election for the European parliament.
It is out of the question to vote for any Conservative candidate. To cast such a vote would be to sanction immorality, greed, law-breaking and corruption.
There are two reasons for this. The first is that Tory MEPs are part of the same expenses racket that has shamed Westminster.
For example, consider this statistic: MEPs have access to an annual £366,000 expenses pot, far more than the £144,000 enjoyed by MPs in Westminster.
Unfortunately, we do not know how they spend this money. Indeed, only six weeks ago MEPs (including the vast majority of Tories) voted to keep their expenses secret.
The second reason it is impossible to vote Tory is that next week's European elections offer the first chance for the nation to deliver a verdict on Westminster corruption.
Of course, Labour and LibDem MPs have behaved just as badly as their Tory counterparts.
And it is not right to vote for these two parties either. Furthermore, Cameron and Brown have one thing in common.
They have both evaded the real issue when it comes to cleaning up their parties in Westminster.
They have focused the blame on peripheral figures such as Labour's Margaret Moran (who claimed £22,500 for treating dry rot at her partner's home in Southampton, 100 miles from her constituency and from Westminster) or Tory Peter Viggers (who claimed £30,000 for gardening, including £500 worth of manure and a £1,645 floating duck island).
Meanwhile, both party leaders have protected more senior MPs. For example, Brown gave a clean bill of health to Transport Secretary Geoff Hoon, Work & Pensions Secretary James Purnell and Chancellor Alistair Darling.
Yet all three are tax-cheats whose conduct, if replicated by an ordinary member of the public, would undoubtedly lead to a criminal investigation.
These men should not be allowed to remain in British public life.
Cameron is guilty of the same inconsistency. While being tough on some backbenchers, he seems blind to the fact that a number of his Shadow Cabinet have been guilty of loathsome and amoral conduct.
I would never vote for a political party which includes Francis Maude (who claimed almost £35,000 for a mortgage on a London flat a few minutes' walk from a house he already owned and then rented out) or Alan Duncan (who submitted thousands of pounds of expenses for his garden before agreeing that the spending 'could be considered excessive').
There are also major questions about the conduct of Shadow Education Secretary Michael Gove (who spent more than £7,000 in five months furnishing a London property in 2006 before 'flipping' his second home designation to a new property he bought in Surrey) and the Shadow Home Secretary Chris Grayling (who got thousands of pounds to renovate a London flat only 17 miles from his constituency home).
As a result of this disgraceful state of affairs, for the first time in 30 years, I have been racking my brain for an alternative to voting Tory.
It goes without saying that it is impossible to support a racist party such as the BNP. Also, UKIP, the most obvious choice, can immediately be ruled out because one of its MEPs is facing prosecution for fraud.
This leaves those of us seeking politicians of integrity and decency with just two possible parties: Jury Team and Libertas.
Jury Team is a new political movement set up by philanthropist Sir Paul Judge, who has an outstanding record as a businessman and has donated generously to many charities.
His own integrity is beyond reproach and his list of candidates standing next week are independent figures (his team includes Esther Rantzen and former anti-sleaze MP Martin Bell) who are determined to clean up politics.
Meanwhile, Libertas was founded by charismatic Irish businessman Declan Ganley who, in a referendum, persuaded Irish voters to reject the Lisbon Treaty which would have given Brussels many more powers.
As a result, the British people already owe Ganley an enormous debt of gratitude. Equally, the European political class hate him - spending hundreds of thousands of EU money on a propaganda campaign linking him with a CIA plot devised by U.S. neo-conservatives to weaken the EU.
Significantly, this smear campaign has failed.
At a time of moral squalor and decay in Westminster and Brussels, both Libertas and Jury Team offer voters a hugely refreshing - and, perhaps, the only proper - alternative on Thursday.