We are in the middle of three days of mourning. This week's conference is the funeral of the Conservative Party.

But shed no tears. Don't let me hear wailing over the Tees or the lovely dales of Durham and North Yorkshire. For this is not a sudden death. The Tory Party has been terminally ill for a long time.

Its illness did not seem so serious at first - just a little hiccough among some of the grandees who glanced at Tony Blair's image of Cool Britannia and thought: "We could use a bit of that ourselves. Let's modernise the image of the Tory Party".

But, unfortunately, this is precisely how diseases develop their terrible course. Serious and even life-threatening illnesses often start with the mildest symptoms, a little niggling nuisance you think you can throw off.

What the Tories ought to have done was seek help at the first sign of trouble. As soon as the word "image" and that other word always associated with it, "marketing" began to be heard around HQ, there ought to have been emergency surgery to cut these things out.

Instead the disease was ignored until it reached the sorry condition which we see today. But at least we can put a name to this dread disease, rather a long name I'm afraid: it is Creeping Leftism with Compassionate Centrism.

A consultant at the spin-doctor clinic described it to me: "At first we notice that the patient develops this irresistible urge to grin all the time. Then he becomes vague about things he always used to hold as sacrosanct. He doubts, for instance, whether it will be possible to cut taxes. He refuses to see that the health service is failing disastrously and could be rescued only by wholesale privatisation. Typically, the Tory patient remains in denial and refuses to go in for the necessary surgery.

"Without treatment, the second stage of the terminal illness begins. The patient becomes woolly and confused about fundamental principles such as the duty to abolish inheritance tax, to support the public schools and to get rid of the policy of university entrance on class grounds. It is at this crucial stage in the progression of the disease that the patient neglects to attend to his pension - or to all our pensions, actually. He looks around him and sees all these politically-correct non-jobs in the public sector and again makes promises to deal with the problem, but ends up doing nothing about it. His mind becomes affected at this stage and he is typically obsessed with crime, but he will make no commitment either significantly to increase the presence and powers of the police or to promise to lock up criminals for a long time.

"The Tory patient is now in a sorry condition. His mind starts to go and he refuses to acknowledge plain truths about himself. For example, he gibbers and froths at the mouth about national sovereignty but forgets that he has signed up to every EU treaty to diminish Britain's independence. He is now in complete denial."

It is all so tragic. Only a year or so ago the Tory patient's disease could have been cured. Now we have only the funeral oration to prepare: "Maggie, thou shoud'st be with us in this hour".

* Peter Mullen is Rector of St Michael's, Cornhill, in the City of London, and Chaplain to the Stock Exchange.