Slightly depressed to read that, although Jaguar has a diesel powered XK up and running, the decision as to whether it will be sold or not will not be made until the end of the year, making a production model an unlikely prospect before 2011.

If this really is down to a fear that it will steal sales from the 5.0-litre normally aspirated version, I fear the short-sightedness that once plagued the British motor industry has yet entirely to vacate the Jaguar premises.

It is course a given that Jaguar will make more money per car on 5.0-litre petrol XKs than 3.0-litre diesel versions and it’s also understandable that having gone to all the effort and expense of designing an all new direct-injection V8 motor that Jaguar will want to maximise the return from that investment. But a logical extension of this thinking is that the better an XKD is, the less likely it is go on sale.

There is, surely, an even more urgent imperative here, and that is to sell cars. For obvious reasons in this market, sales of the 5.0-litre XK are likely to be on the slow side, not least because its emissions place it in the same top taxation bracket as the XKR for both company and private users.

But an XKD can draw a real distinction between it and its full-fat sister, costing massively less not only to buy but also to run and tax. It will provide good and relevant reasons to buy an XK that have never existed before, and when the timing could hardly be better.