Talking to the Berliner Morgenpost, Dieter Faulenbach da Costa, who was responsible for planning the project up until 1999, said he doubted whether the airport would ever be opened.

Berlin-Brandenburg Airport (BER) was supposed to open to the public in 2011, providing the German capital with a modern transport hub to replace the smaller airports at Schönefeld and Tegel.

But a series of planning failures have delayed the opening by years, with city authorities now claiming it will open in 2017.

Da Costa believes though that modifications to the design of the fire safety systems, which are the main reason for the delay in the opening, will make the project unworkable.

“The restructuring of the fire safety systems which has been going on for the last four years at BER will prevent the opening of the new airport,” he told the Morgenpost.

Da Costa criticised the airport management for too hastily ditching the old fire safety system.

“Instead of completing the apparatus which complied with original construction permit and then testing it, they decided to take on restructuring projects,” he said.

Berlin authorities responded to the former planner’s comments by saying it was sticking to the scheduled opening at the end of 2017.

“We already commented fully on this problem and to our current plan for the opening on Friday. We have nothing more to add,” spokesperson for the airport Lars Wagner said.

Earlier in April the airport sacked its previous PR chief for being slightly too honest about failures in the project.

Daniel Abbou described previous management as a “shit show” and said “up until now official statements always said that the project was going well. That’s bullshit.”

Due to the chronic delays, the state governments of Berlin and Brandenburg are also likely to have to pay out millions in compensation to airlines which planned their businesses around a 2011 opening.