Quite a lot of Jools Holland's conversation works like this - starting almost officiously informative, then straying off the straight and narrow into vaguely wacky territory before losing its sense of direction altogether. It is entertaining, endearing even, though slightly maddening when you come to transcribe it. It has got him into trouble, too - as when he used a four-letter word during a live trail for The Tube. (For younger readers, this was a rather good Friday-teatime pop programme presented by Holland and Paula Yates, in the early days of Channel 4.)
So now he pays a little more attention to what he says. Indeed, for the Saturday- night pop programme he is working on at the moment, the third series of the appealingly eclectic Later with Jools Holland, he is using cue cards for the first time: because, he says, it has a very complicated format, and because he doesn't reckon he's a very good presenter anyway - 'too relaxed'.
If Holland doesn't seem fazed by television, it's probably because he thinks of it as just a sideline: what he really is, in his own estimation, is a musician. He is still thought of as the former keyboards player with Squeeze, though his interests have moved away from the group's friendly, wordy pop. In the early Eighties, when the band temporarily split up, he started his own group, the Millionaires, losing money on the album and subsequent tour. He also started playing with Squeeze's drummer, Gilson Lavis, whom he used to introduce, for a joke, as the Jools Holland Big Band. Holland and Lavis kept gigging, gradually adding a bass, a guitarist, a horn section . . . until, incrementally, it became a genuine big band. Since 1990, this has occupied 75 per cent of his time. Two albums, The A to Z of the Piano and A World of His Own, have sold 'respectably', and the band now resides on Don't Forget Your Toothbrush (as if to pre-empt criticism, Holland points out that you can't just send the players home when they're not on tour; they have to do something).
The Big Band allows Holland to indulge his musical passions - blues and boogie-woogie. He started playing the piano at the age of eight, when his uncle taught him 'St Louis Blues'. The young Holland would pound out the same tune for hours at a time in his grandmother's front room, a few streets away from his parents; apart from brief forays to New York in the Eighties, he's always lived in south-east London, and attributes his pop success to this: 'Most musicians in bands come from suburbs of cities. They all come from Pinner or Dartford - I'm thinking of the Rolling Stones and Elton John - but never from Mayfair or Belgravia or anything.'
He enjoys this sort of theorising. His main interest, apart from old cars, is architecture - practically anything, he says, except Frank Lloyd Wright and Gaudi ('Quite impressive, but you wouldn't want to live in it'). He has a theory about the relationship between the blues, in which the central chords are fourths and fifths, and the proportions adopted by Palladio.
When he'd mastered 'St Louis Blues', he bought a record of Jimmy Yancey, Pete Johnson and Albert Ammons - 'I used to feel as if they were my three great big spiritual uncles' - and tried to play like them. Boogie-woogie, he feels, is an artificial category, but a rolling, striding bass is still his most characteristic mode.
So music occupies his time - and brings in most of his money - but the visibility comes from television. For somebody who claims he isn't very good at it, he has been highly successful.
On The Tube, his informed enthusiasm and heavy irony provided a necessary counterpoint to Paula Yates's breathy flirtatiousness. Later, he made a Channel 4 special, Walking to New Orleans, followed by a programme on the music of Memphis ( Chicago follows shortly). There was also a short-lived BBC revival of Juke Box Jury. And in the mid-Eighties he presented an American show, Sunday Night, which prefigured Later - gifted musicians, playing not miming, in the studio not on video - with the important difference that the US version didn't allow for new talent. When Jools discusses the purpose of Later, he talks about 'informing, educating and entertaining'. He's Lord Reith in drainpipes.
This seriousness - in basic intentions, though not in presentation - stands behind the series' success. Later has established itself as the best rock or pop programme on television. Musicians actually want to appear, even unpaid. The new series will feature the first live gigs in this country by the re-formed Elvis Costello and the Attractions, as well as Traffic, Otis Rush and Dr John ('one of the greatest pianists of all time').
They want to be on because, Holland says, 'they know that it's straight, and that it hasn't got funny items about fashion or they're not going to get squirted with a water pistol'. No doubt these negative virtues work in its favour, but you suspect, too, that for many musicians it has one positive factor on its side: and that is Jools Holland.
'Later with Jools Holland': 10.20pm Sat, BBC2, for seven weeks.