He married in a kilt, supports Rangers, drinks Irn-Bru and speaks English with a gentle Scottish lilt, all of which might not be so unusual were it not for the fact that David McAllister could one day be the chancellor of Germany.

The 41-year-old has been described as the "crown prince" of the current German chancellor, Angela Merkel, whose Christian Democratic Union (CDU) he has been a member of since his youth. "Some even call me her pet," he sighs, raising his eyebrows in exasperation.

But the half Scot, who was born in West Berlin to James McAllister, a British army father from a working-class part of Glasgow who was serving with the Signal Corps, and a German music teacher mother, Mechthild, says he has no designs on Berlin. He is happy for now to stay in Lower Saxony, northern Germany, where he is state prime minister and responsible for 8 million Germans and a budget deficit that he has ambitiously promised to slash to zero if re-elected.

While coy about Berlin in one breath, in the next he reels off a long list of leading politicians in Berlin, past and present, who started their careers in Lower Saxony, including former chancellor Gerhard Schröder, former president Christian Wulff, and both the current ministers of labour and economics.

"I know the media is having a closer look at the next generation," he says, all of which adds up to a subtle admission that a high-ranking position in Berlin, possibly even the chancellery, would be a future he could in fact envisage. "At the moment I'm by far the youngest minister-president [state prime minister]," he says. "Though [former chancellor] Helmut Kohl was half a year younger than me when he became a minister-president."

He knows the media – in particular the British – would have a field day if he made it to the top. He says he is already the focus of intense curiosity, particularly for the Scottish media. "They find it intensely amusing that there's a German politician who knows what Irn-Bru is, who knows The Broons and Oor Wullie (a classic Scottish comic strip), who knows about the Beano and Dandy, Marmite, porridge and custard."

He is still working on getting Germans to pronounce his name correctly. 'McAllister proves to be a bit of a tongue-twister for some, and he is usually nicknamed "Mac". "'Meck-Al-Ister' is how most say it," he says. "Sometimes I get M-C-Allister. It's strange, isn't it, when you have a McDonald's every 500 metres in Berlin?"

Childhood consisted of growing up in what he refers to as "Little England", the British military sector in the heart of West Berlin's Charlottenburg district, where streets were named Hardy, Dickens or Brontë Weg (way). "I had a British upbringing in the middle of West Berlin. We had British buses, wore school uniform and spoke English at home. My dad would always bring the Telegraph home from the office, and we listened to BFBS (British Forces Broadcasting Service) all day, including the football results read out by James Alexander Gordon."

He describes "turning German" at the age of eight, when his parents decided to stay in Germany, and he was put into an all-German school. He'd later do his military service in the German army, but has retained both German and British passports. But he admits that his Britishness has remained an important part of his identity, particularly his sense of humour, "a dose of which would be good for German politics".

He enjoys watching the rowdy Commons debates on YouTube, and wishes German politicians could learn a thing or two from them. "Compare a debate there with the Bundestag and it's like two different planets. German MPs are very straight, dry, unemotional. What I like in Britain is that they have a good slanging match and afterwards they drink a beer together."

Unlike many of his German Christian Democrat colleagues, he stays in touch with the British Conservatives. As anyone with an eye on both systems knows, the ideological differences between the parties, most glaringly on Europe, are vast. "I keep contact with the Conservatives even though not many in the CDU do – it's a difficult relationship," he admits.