State PM David McAllister exploits his Scottishness and financial prudence in campaign seen as litmus test for Angela Merkel's run in 2013

As the bagpipes struck up, the crowds started to clap rhythmically and a beaming David McAllister, flanked by bodyguards, appeared to float into the room through a sea of orange and blue placards that read "I am a Mac".

Having checked that Apple never patented the slogan in Germany, the Christian Democratic Union (CDU) adopted it as the campaign slogan for the man seen as the future of the party and the most obvious successor to chancellor Angela Merkel. Now it appears not just on placards, but scarves, T-shirts, even a smartphone cleaner being distributed at his rallies.

Many German politicians try to play down their roots if they have a hint of anything un-German about them. Not so McAllister, whose Scottishness – his father was born in Glasgow – has only served to boost the CDU's re-election chances on Sunday in the state of Lower Saxony, where he has been prime minister since 2010.

"It makes Lower Saxony more international, more outward looking that we have him," said Ursula Schaub, 60, who had brought her nephew, a first-time voter, to McAllister's penultimate rally in the north-western city of Osnabrück on Wednesday evening.

While McAllister stresses how he served in the German army and has spent all his life in Germany, in the runup to these elections he has played on his Scottish roots for all they are worth. "Schottische Sparsamkeit" (Scottish thriftiness) has been an oft-repeated phrase as McAllister pledged to the 3.9 million voters that he would be the first person since another Scot, Gordon Macready, who ran Lower Saxony when part of the British zone following the second world war, to balance the state's books.

German voters may not be able to pronounce his name, putting the stress on the "ister", but they do cherish fiscal prudence, affectionately referring to the sales seasons as "Schottentage" or Scots' Days.

Yet far more is at stake on Sunday than a balanced budget, such as childcare provision and traffic bottlenecks. The vote, in Germany's second largest state by area and fourth largest by population, is being seen as a test run for next autumn's general election .

The politician that Merkel hopes will deliver an election victory for her centre-right party is himself using what he calls the "tailwind" of her national popularity to fend off strong competition from the opposition Social Democrats and Greens.

But his achilles heel is the pro-business Free Democratic party (FDP). As on the national stage, so too in Lower Saxony it is a CDU-FDP coalition that governs.

With the FDP polling well below the 5% threshold necessary to enter parliament, McAllister might yet be deprived of leadership despite the CDU's strong poll lead. If the FDP fails in Lower Saxony, political observers say it is highly likely to fail at the federal level in September. Not only could the 42-year-old McAllister end up losing his job, but Merkel, too. If that happened, the CDU's most promising politician would probably find himself with a ministerial position in Berlin in what could accelerate his rise to the chancellery.

McAllister brushed off such concerns and speculation on Wednesday. "You are looking at the winner," he told about 2,000 people who had stomped through snow and braved freezing temperatures to gather in the Osnabrück Halle.

"I am proud to be Merkel's Mac," he said, referring to the slightly derogatory nickname given to him by Germany's popular press, who have often referred to him as the chancellor's lapdog. "I'll tell you one thing, that's a huge compliment, for you, dear Angela Merkel, are Germany's biggest asset," he said gesturing to the chancellor who stood on the stage next to him.

Merkel ,who will have been on the stump with McAllister for a record number of eight rallies, returned the gushing praise. Pronouncing his name "Meckallister", she referred to him as "storm-proof" and "down to earth". "He embodies the role of 'father of the state' completely and utterly," she said.

But alluding to the popular suggestions that he is her "crown prince", she said to laughter: "As much as he enjoys coming to Berlin, he enormously enjoys going back home." As she spoke, McAllister, leaning on a lectern sipping water, had the dreamy-eyed look of someone listening to a nightclub crooner.

Oskar Niedermayer, politics professor at Berlin's Free University, said: "This election completely sets the tone for the federal election as whoever wins in Lower Saxony will have much better cards than those who do badly," he said. Calling the poll "dramatically important" for the future of the FDP, Niedermayer said he expected its leader, Philipp Rösler to resign on Sunday night, even if the party narrowly squeezed into the state parliament. "That will have to happen if the FDP wants a chance of succeeding in September."

But, for now, the spotlight is on McAllister, who marched, Braveheart-style, out of the campaign rally to the CDU's election anthem, a punchy bagpipe rock number whose lyrics include the line: "Our chieftain is a Scot and we are a strong clan."

He is clearly tickled by the unusually high level of international interest in his campaign. "Even the Scottish tabloids have been here and are taking an interest in German politics," he said, switching from German to a light Scottish-accented English as supporters crowded round asking him to sign their placards and pose for photographs. "Although this is a regional election of course we're well aware that it has an impact on the federal level. If the 'I am a Mac' slogan, which is something like a wink to the voter, helps with that then so much the better," he said.

He then spotted a Scot in a kilt, 51-year-old John McGurk. Like McAllister's own father, McGurk came to Germany as a soldier, married a local woman and ended up staying. McGurk would not reveal how he would vote on Sunday, but said: "David is liked because he's got a lot of charisma, he's down to earth, he gives the place a sort of international flair – and apparently because we Scots have this reputation for being careful with our money, which I hadn't realised we had until I came to Germany."

Profile



David McAllister proposed to his wife at Loch Ness, married in a kilt, he likes Irn Bru, shortbread, and porridge and takes milk in his tea.

A holder of British and German passports, he supports Rangers, who are top of Scottish Division Three – as well as Hannover 96, who are having a middling season in the Bundesliga.

Born to a Glaswegian father, James McAllister, who came from the Gorbals, and a German mother, a music teacher called Mechthild, he was brought up on the classic Scottish comic strips The Broons and Oor Wullie, and on James Alexander Gordon reading the classified football results on Saturday afternoons on the British Forces Broadcasting Service in Berlin.

Unlike most CDU politicians, he keeps close ties to the British Conservatives despite their differences on Europe. But his connection with the Scottish National party is even closer.

Of the handful of people he follows on Twitter, two are SNP politicians. One is the leader, Alex Salmond, who on a November 2012 visit to Lower Saxony to sign deals on renewable energy projects with Scotland presented him with a rare bottle of whisky he has otherwise only given to Prince Charles and Arnold Schwarzenegger.

The other is Westminster SNP leader Angus Robertson, who like McAllister is half-German, half-Scottish, of whom he once joked "we should form the German-Scottish Parliamentary Union – we just need another five to join us." Robertson said: "It's a great thing to have such a senior and respected political leader in Germany with strong connections to Scotland."

McAllister retains ties with relatives in Newton Mearns, and speaks English to his two daughters at home in Bad Bederkesa. He refuses to be drawn on the issue of Scottish independence though, as a potential future leader of Germany, he may well one day find himself having to take a decision on Scottish membership of the European Union.

• This article was amended on 21 January 2013. McAllister and his family live in Bad Bederkesa, not Hanover. This has been corrected.