This is a selection over which to linger, but Elton's schedule will not permit slow lunching deep into a relaxed afternoon. He's arrived accompanied by a publicist, whose job it is to make sure he moves seamlessly to the next interview, on time, and the next one after that. And the next after that.

Elton has come to this Southbank restaurant from the nearby ABC studios; later are a TV spot and more interviews. He has a new book, Two Brothers, a historical novel about the fate of two brothers in Nazi Germany.

His schedule is punishing. Germany, France, then a week in Britain (where he is working on a new BBC sitcom) before jumping on a plane to Australia. He's jet-lagged, although it doesn't show. ''I'm all over the place,'' he says.

And so to the menu. The restaurant's express lunch has immediate appeal and the gourmet beef burger is tempting him. ''A good beef burger's always hard to beat,'' he says, although he dislikes what he says is an Australian habit of putting it on ''poncey'' bread. ''You cut your bloomin' gums,'' Elton complains. ''Crunchy bread around a burger is ridiculous. So by all means improve the meat in a burger but don't mess with the bread.''

In a nod to the restaurant's theme, he chooses the sensibly sized 200 grams of rump eye, grilled to his liking: medium. ''If it's all right by you, I'm going to have a nice steak and chips,'' he says. Mine is a warm beef salad of New Yorker steak, marinated in thyme, oregano, lemon oil and chilli.

''If everyone would agree to be a vegetarian, I'd go with it because I know that meat is destroying the world,'' he says. ''But having said that, I do love it. And roast beef and Yorkshire pudding is my personal signature dish. You must say, if you quote that, 'He puts on a poncey voice to say a poncey thing'.

''My Sunday roasts are a huge part of our family life. And I do love it very much.''

At 53, Elton shows no signs of Yorkshire pudding overload. He also likes to drink wine, but not today, lest he fall asleep mid-interview. ''I have a definite principle, and that is that 20, 25 years ago, I made the decision. I love to drink. The food I like is chips, Yorkshire puddings,'' he explains. ''So I started to exercise. I exercise hard and the reason I do is so that I can earn the things I like to consume.''

In Fremantle, where he lives with his Australian wife, Sophie Gare, and their three children, he is a regular on the Swan River, where he has become an evangelist for paddle boarding. ''It's the ultimate middle-age exercise,'' Elton says, leaping up to give a demonstration. He ponders if it's possible on the Yarra below us.

I tell him the book is having an impact on me, and he's pleased with the compliment. Two Brothers is the story of Paulus and Otto, twin sons of a German-Jewish family. Hitler's rise forces the revelation of the secret that one of the ''twins'' is, in fact, not Jewish but adopted. They end up serving on different sides in the war.

The story has a resonance in Elton's family. His father, Ludwig Ehrenberg, was a Hitler refugee; his family made it to Britain via Czechoslovakia in 1939. Ludwig's older brother, Gottfried, enlisted in the British army. Their cousin Heinz was adopted, and after his parents fled Germany, he stayed to farm before being drafted into the Wehrmacht. The book is dedicated to the two men.

But Elton is quick to stress that beyond that connection, the work is not ''remotely'' a family history. He does not feel a right to claim extra credibility to write about the subject. ''My commitment to this novel is as a human.'' He is, he says, only a ''single individual attempting to understand a terrible time''.

The book is the 14th from Elton, whose career spans a remarkable and successful body of work across a range of genres. In the early 1980s, he began as an edgy, left-wing, anti-Thatcher stand-up comedian, had significant success as a scriptwriter (The Young Ones, Blackadder) and then musicals (We Will Rock You).

''It's all writing to me,'' Elton says. ''It's all the same job.'' He thinks it's a question of opening his mind to the possibilities. ''I find it all the same process of imagination, the same process of improvisation.'' He writes because he is driven by an idea, rather than writing to create a success. Elton acknowledges his ''great good fortune'' in being successful early in his career gives him financial freedom, which is an ''unimaginable'' privilege for an artist.

As we eat, we return to the subject of fitness. Elton relates how he harangued a government official who was claiming credit for plain cigarette packaging. He doesn't argue with smoking restrictions, but told the official he was ''coming after ya'' if he started putting pictures of rotting livers on wine bottles. ''When did we elect a government to wag its finger at us, at every possible pleasure?''

Elton is fired up, and it's more than the jet lag speaking. He rails against what he says is ''far too slavish an admiration of accumulation of wealth'' in Australia.

''I find the fact that billionaires are quoted as if the fact that they are billionaires gives them some kind of wisdom is outrageous. I think it's a terrible thing that the centre ground of the debate about social responsibility has drifted so far to the right in Australia.'' Elton speaks with the authority of being a dual Australian-British citizen.

If he had two lives, he would love to go into politics. ''I don't believe all politicians are bastards. I don't believe they are all self-interested swine on either side.

''Sorry,'' he says, ''I've been banging on, and I didn't even have a drink!''

The publicist has returned, but there is time for coffee and the subject of his next book. He loves history, and would love to write another historical novel. Because of the period, he says, Two Brothers was distressing. ''But it was very satisfying, and I would love to do it again. And I am thinking hard: what would I love to write, what do I know, what can I imagine?''

■ Two Brothers is published by Random House.