By Madeline Chambers and Holger Hansen
BERLIN (Reuters) - The German capital will replace its party-loving mayor Klaus Wowereit with little-known politician Michael Mueller, the city's Social Democrats (SPD) decided in a vote on Saturday.
Wowereit, famous for describing Berlin as "poor but sexy", announced in August that he would quit in December, two years before the end of his term. Since then three SPD candidates have been jostling for support.
In a vote of Berlin's Social Democrats, Mueller, won 59.1 percent, unexpectedly avoiding a run-off vote. The conservative Christian Democrats (CDU), who share power with the SPD in the city state, have said they will back the winner of the SPD vote.
The city, which was until 1989 the frontline of the Cold War, has plenty of challenges awaiting the 49-year-old bespectacled senator for development and environment.
A top priority will be finishing the new international airport, he has said. The project is five years behind schedule and is running at twice the original budget. The delays and cost overruns have hurt Germany's reputation for efficiency.
SPD Chairman Sigmar Gabriel said Mueller would continue the work of Wowereit, who championed tolerance, while setting his own tone.
"Under his leadership social justice and economic growth will be measures of political action," said Gabriel.
Mueller, who was born in Berlin and is a printer by profession, has a reputation within his party for being something of a dry politician.
He acknowledged as much himself in a light-hearted way during the campaign for mayor, saying: "I know there is room for improvement in the glamour factor."
Mueller has vowed to continue efforts to cut the city's debt which is almost twice the national average on a per head basis.
Almost 25 years since the Berlin Wall fell, many parts of the city still look like a building site. Its schools ranked bottom in a recent federal table and some 17 percent of residents live on welfare.
It generates just 4 percent of German output but Berlin's economy is growing faster than the German average. It has experienced a property boom in the last few years and has a lively Internet start-up scene.
Senior Berlin SPD members Jan Stoess and Raed Saleh had stood against Mueller but won only 20.9 percent and 18.7 percent of the vote respectively.
Wowereit became a national celebrity by coming out as gay during his first mayoral election. He was popular in the capital and was once seen as a possible leader of the SPD or candidate for chancellor. But a perceived lack of gravitas and the airport scandal put paid to any such ambitions.
(Writing by Madeline Chambers; Editing by Stephen Powell)