At times recently it seemed that his name was permanently etched on the notional marquee over the entrance to Glasgow Royal Concert Hall as he made a succession of visits, in radically different guises, accompanied by the Royal Scottish National Orchestra, the Brodsky String Quartet and then his own latest group of top American roots musicians, The Sugarcanes. Spoiled, we've been. But with a new album, National Ransom, to promote, when can we expect him next?
"You're right, it's some weeks since I've been in Scotland," he laughs, and reels off each of the recent dates. What they illustrate, of course, is that Costello, individual as ever, works in his own way.
"Things don't have to happen the way they used to: album, tour, T-shirt, videogame. There has to be more to life than that. I just do what works best for the music in different kinds of concerts. But I've no idea of the exact time."
In fact five of the songs on the new album were additions to the repertoire of the Sugarcanes after the recording of the Secret, Profane, And Sugarcane collection. Another song he played then, "Condemned Man," didn't find a place on the new disc, which has some 16 new songs.
Costello is as prolific as he always was and busier than ever. He is in New York as part of an all-star line-up assembled by the producer of the new album, T-Bone Burnett. Burnett it was who revitalised Robert Plant's career by teaming him with Alison Krauss on the Raising Sand album and who is about to perform a similar service for Elton John's credibility with an album that teams him with US piano veteran Leon Russell. His charitable Speaking Clock Revue shows feature a rolling cast of new and rediscovered names combining their talents in the sort of fluid context that Costello – whose partnership with Burnett goes back to the 1980s – revels in.
Some of these associations inevitably crop up on National Ransom. "My Lovely Jezebel" is the fruit of a trip Costello made to the John/Russell sessions to find that Elton had departed for the day. In the remaining studio time, he and Burnett supplied lyrics to a tune that Russell composed.
"I first saw him in 1972 and he was fantastic then. If he'd gone anywhere, he's back and he's fantastic now. No-one plays piano like him. Some songs are on the album just for the mischief and pleasure of playing them. It would have been very claustrophobic otherwise. At one time I might have wanted to make that sort of record but not now."
That sort of unbridled enthusiasm for music-making, and fan's delight in working with people he has long admired, is a distinguishing Costello trait, but it sits alongside a compulsion to be the maverick outsider as well, an unwillingness to play the game by anyone else's – and certainly the industry's – rules.
National Ransom, he says, should be thought of as a double vinyl album, because that was what he was making. "I couldn't say that out loud though, because they'd just try to charge more for it. So although it might suit you to have it as a CD or a download, it is two vinyl LPs. They can be a useful weapon," he adds, enigmatically, "or a tray ..."
Of course the songs on National Ransom – performed by a whole troupe of recent and past Costello confederates as well as a guests including country star Vince Gill – carry their share of pointed messages. The Tony Millionaire illustration on the cover is a big hint as to the target of the title song: Wall Street's "wolf at the window", while the dating of "One Bell Ringing" to June 22, 2005 points to its concern with the killing of Jean Charles de Menezes on the London Underground. There is nothing, however, of the vitriol of a song like the Thatcher-despising "Tramp the Dirt Down," from 1989's Spike.
"To write a vitriolic song about a specific event, you'd need a degree of certainty," explains Costello. "This is about the horror of someone's life being taken. There is no assumption of moral authority. In the song 'National Ransom,' I include myself among the guilty because of the interlocking nature of transactions now. But there is a tragic feeling of dread in the air."
There is a consistency about this in Costello's work, which makes his complaint that he is not competing with his past output reasonable.
"There was a cartoonish violence about 'Tramp the Dirt Down' because Thatcher was a cartoonish figure. 'Shipbuilding' [his timely co- composition with Clive Langer about the Falklands adventure] was not a protest song. There's no black and white any more. There's a moral certainty about protest music that is not attractive – and you are only listened to by people who agree with you."
What is unarguable about the bulk of the new album is that it is a collection of compelling stories. Costello has recognised the narrative in most of the songs by putting a location and date at the end of each lyric, placing some of them specifically in hard times earlier last century.
"It wasn't preconceived that way, it was just something I found myself doing. It occurred to me that many of the songs reflect on the moment we are moving through. The record was made in not a lot of time and you see what you end up with."
In fact National Ransom's total recording time of 11 days (in Nashville and Los Angeles) is the same time as Elvis Costello and the Attractions took to make This Year's Model in 1978, with Nick "Basher" Lowe at the controls ("bash it down, and we'll tart it up later"). There was no tarting up here though.
"There wasn't a lot of tinkering. We played live in the studio, not to make any point just because that was a good way to do it. It makes the performance of it more joyful."
That description masks a lot of skilful musical efficiency, however. The song "You Hung the Moon" (about a family's way of coping with the killing of a First World War deserter) comes garlanded with a string arrangement concocted in the same timeframe. With no formal musical education, Costello has gone about acquiring all the skills that might be useful, as his book of charts for the RSNO showed.
"I now have the confidence to write what it is I want to hear," he concedes, "but I had to do it on the fly. I wanted that to sound like a little band show on the radio – and that's what you get."
That nostalgic feeling permeates the new album, a fact underlined by the fact that Costello has also made National Ransom available as a collectable set of 78rpm discs. In a sense he is putting a marker down.
"We are heading for a transition and it might be that we don't make record albums any more. I've no way of knowing. But they were beautiful and they sound good, and we'll have lost a bit of that. And we've still got 100 years of music to listen to and enjoy."
National Ransom is out now on Hear Music.