Berlin’s out mayor has announced that he is quitting at the end of the year, after 13 years in the role.

The city’s Social Democrat mayor Klaus Wowereit – one of Germany’s first prominent gay political figures – has announced that he is to leave office two years early, over an ongoing row regarding the city’s airport.

He was first elected in 2001 and had been due to finish his latest term in 2016, but will now bow out on December 11 this year.

Mr Wowereit came out prior to his first mayoral election campaign, uttering a now-famous phrase: “I’m gay, and that is a good thing” (“Ich bin schwul und das ist auch gut so”).

However, his popularity had fallen in recent years, after controversy surrounding the construction of the Berlin-Brandenburg Willy Brandt airport, which was due to open in 2010 but is still under construction.

He said: “This decision was not easy for me.

“There has been a lot of speculation recently about the question of the governing mayor’s tenure.

“I have to admit that this discussion has also taken place within the ranks of my own party.

“I go voluntarily and I am proud of my contribution to the positive development of this city.”

Germany does not recognise same-sex marriage, but Mr Wowereit has been with partner Jörn Kubicki, a neurosurgeon, since 1993.