Stalled: Berlin Airport budget has swollen from €2bn to €5.4bn, and officials fear it could yet rise to €6.5bn © Bloomberg

The head of the new Berlin airport has been sacked after only two years in the job, in a further blow to a project that is more than five years behind schedule and billions of euros over-budget.

Since work started on the airport in 2006, its official opening has been postponed five times: the complex, which was due to open in 2011, will not now launch before next year.

Known as BER, it has been dogged by technical problems, poor planning and frequent management changes. Its budget has swollen from €2bn to €5.4bn, and officials fear it could yet rise to €6.5bn.

The latest personnel change further reinforced the new airport’s reputation in the eyes of many Germans as a national joke. Airlines had warned against moves to sack Karsten Mühlenfeld saying it would lead to further delays.

“If there were as much air traffic at #BER as staff flying or landing, the air space would be pretty crowded,” tweeted Green MP Renate Künast.

BER’s delayed opening in 2012 was cancelled at the last minute after defects were found in its fire-protection system. It was later revealed that its cooling ducts were uninsulated, its car parks crumbling and smoke extraction system defective. Inspectors also found there were too few check-in counters and baggage carousels.

Earlier this year authorities said 2km of water pipes would have to be replaced because of problems with the sprinkler system. It also emerged that the airport’s electronic doors were not working properly.

Airlines had warned against moves to sack Karsten Mühlenfeld saying it would lead to further delays © AP

Mr Mühlenfeld was removed after he had replaced the airport’s project manager Jörg Marks, against the wishes of the supervisory board. Mr Marks was reinstated on Monday.

German media reported on Monday that Mr Mühlenfeld would be replaced by Engelbert Lütke-Daldrup, a city planner who previously worked in the Berlin regional government. He will be the fourth BER boss since work on the project began in 2006.

It was also announced that Berlin’s mayor Michael Müller would leave the airport’s supervisory board.

The airport is owned by three different authorities — the federal government and the governments of Berlin and Brandenburg, the region surrounding the capital. Representatives of Berlin and the federal government on the supervisory board had been pushing for Mr Mühlenfeld’s removal, but Brandenburg resisted. It finally backed down on Monday and joined calls for the chief executive to quit.

Mr Mühlenfeld took on the job in 2015, replacing former Deutsche Bahn boss Hartmut Mehdorn, who stepped down after clashing with the supervisory board.