OSLO, Sept 14 (Reuters) - Norway"s presumptive next prime minister is a man born into wealth and privilege who became an unlikely leader of the Labour Party, traditionally seen as the political voice of the working class and which built the country"s welfare state. Overcoming his 2017 election defeat and internal party turmoil, Jonas Gahr Stoere, 61, is expected to replace Conservative Prime Minister Erna Solberg, 60, as tallies showed a decisive swing in favour of the centre-left. read more The son of a ship-broker and heir to a fortune worth some $16 million, according to business magazine Kapital, Stoere"s elite background was once deemed an obstacle to his ambition to lead a party rooted in the struggle for workers" rights. He has promised that it"s "common people"s turn", pledging to reduce inequality by giving tax relief to low and middle income families, cut the cost of public services and hike taxes for the rich - including himself. A former foreign minister and health minister, Stoere has led Labour since 2014 but stumbled at his first attempt to win power in 2017 as Solberg"s Conservative-led coalition came from behind to win a second term. This time, the combined centre-left has won its biggest victory in almost three decades, with Labour as the largest party in parliament. Stoere must still navigate tough post-election coalition talks with two other parties, however. To form a majority government, he would need support from the rural-based Centre Party and the Socialist Left, which have contradictory policies on everything from oil production to taxes. He could rule in a minority, but with only an estimated 48 seats out of a total of 169 in parliament his government would be vulnerable. Labour"s eight years out of power is the longest since it first formed a government in 1928. The party has ruled for about 50 of the 76 years since the end of World War Two. NO YELLOW VESTS Stoere says the class differences he observed while studying in Paris in the 1980s converted him to social democracy. "I learnt what kind of society I wanted to live in. In France, differences between people are large, larger than in Norway - between rich and poor, between those with education and those without, between city and countryside," he wrote in a column for Norway"s ABC News website in 2017. Stoere told Reuters last month that distributing the economic burden more evenly would ease the introduction of stricter climate policies - a major issue in Norway, which grew rich on oil, still the country"s biggest industry. "We need to avoid yellow vests. We must ensure we cut emissions and create jobs," Stoere said, referring to the French "yellow vest" anti-government movement. Norway was "good at negotiating these transitions", he said, "but we must have a society with fewer differences, which have increased with the past government". Studying at Sciences Po, one of France"s top universities, Stoere travelled to the Soviet Union as part of the movement to support Soviet dissidents. After returning home, he worked closely with Norway"s first female prime minister, Gro Harlem Brundtland, and was later her chief of staff at the World Health Organization. In 2010, as foreign minister in his friend Jens Stoltenberg"s government, Stoere secured an end to a four-decade-long offshore Arctic offshore border dispute with Russia. He then served as health minister before becoming Labour leader when Stoltenberg was appointed NATO chief in 2014. Norway is a founding member of NATO. It is not a European Union member but has close economic ties with the bloc that could become a sticking point in coalition talks. read more Stoere managed to hold on to the Labour leadership after 2017, when the party started the year with a large lead in opinion polls but lost an election after pledging to raise taxes and as an economic recovery boosted Solberg. For the 2021 campaign, he kept middle-class voters on side by making clear that only the top 20% of earners and the very wealthy would see their taxes rise if Labour won. Editing by Catherine Evans