... you could bottle it.

That's the thing, it's such a disparate collection of elements which are in themselves difficult to define. Groove, for example. I don't know how to describe it, but I know it when I hear it.

I think one of the best people to ask about this might be Guy Chambers, the guy who wrote all of Robbie Williams's biggest hits. He's the very definition of the write-em-to-order hit songwriter. Judging from his work, I'd say a hit might contain any of the following:

- Vague lyrics which could mean almost anything;
- a strong instrumental hook;
- a very simple chorus, consisting of no more than one phrase;
- a verse whose melody doesn't move much. No big leaps.
- a big leap up to the chorus, which then doesn't leap any more.

Other than that, I can't identify anything much that is common to all his hit songs - not even groove or movement. Look at "Angels" - it's tedious in the extreme, but it sold by the fucking bucket.

there is less and less "magic" involved in defining a hit record: the music or song often seems incidental to the process of making a record a hit. It's just glorified karaoke these days: a backing track with digitally air-brushed production with a face that fits the moment fronting it. If they can hit the right notes without auto-tune it's small consolation.

There is still great music being made but the correlation between great music and hit music grows further apart. Personally I think some of the best hit records made in recent years have been by Girls Aloud. Somebody was savvy enough to factor a song-writing team into the mix, i.e. Xenomania, rather than just rely on the sex appeal. You just have to look at the dire songs Cheryl Cole's released under her own steam to appreciate that Girls Aloud have had some cracking singles.

I can live with Xenomania, in fact I hope we get more song-writing teams like them. As an analogy how often do films forget about the script these days, relying on crashes, bangs and whallops to carry the "story" and relegating the script to simply telegraph a plot development? You need writers to have any chance of sprinkling any magic at all.

So having a 21st Century Brill Building in Xenomania to remind us all that songs are written by humans, despite being delivered by pretty plastic people acting as the shop front to musical data warehouses, is a good thing in my book.

I would say tune and lyrics. Hit Me With You Rhythm Stick is a near perfect mix of lyrical brilliance, great tune and proper, funky rhythm. I Wanna Be Straight is great, but not as good.

Is there a case for saying that I Wanna Be Straight is too obvious, too hummable, too soon? It's such an infectious earworm that I had to switch it off during a first listen as it was actually beginning to bug me - and then it remained in my head for the next couple of hours, not entirely pleasantly. Rhythm Stick, by contrast, is a far more slippery customer. You want/need to hear it again, just to try and assimilate its strangeness. Yes, it has some great, obvious hooks, but it also has real character and a mystery and a mystique to it. It doesn't offer up all its charms on a first listen - there are nooks to explore, lyrics to grasp. Lady Ga Ga's Bad Romance is similar in that respect - and look what a hit that was.