After invitations to an opening ceremony with Chancellor Angela Merkel in attendance had been sent out, the local official responsible for certifying the building's fire safety called a halt. He had discovered that a supposedly sophisticated system of detectors and automated alarmed fire doors was not functioning.

Those running the building had instead been working with makeshift systems, which included temporary employees sitting by doors to raise the alarm with mobile phones.

Mayor Wowereit and colleagues from local, regional and federal government had to announce, in a humiliating press conference, the grand opening could not take place.

Suddenly, the astonishing scale of the new airport's problems emerged.

New construction boss Hartmut Mehdorn made a list of all the faults and failures, Mr Delius tells me.

"Small ones like the wrong light bulbs to big ones like all the cables are wrong," he says.

The final total was 550,000 - more than a half a million problems to fix.

What you might call chaotic cabling has been the curse of this project - and it's still dangling over the whole enterprise.

They have had to put in "many hundreds of kilometres of new cables", Mr Dorn says, to replace what was originally installed.
And costs have gone up all the time, with millions spent each month maintaining the building.

So, the airport of no arrivals has, in financial terms, passed the point of no return.

The final sum will be paid mostly by German taxpayers, who have come to view the whole saga with emotions ranging from rage to boredom to very black humour

And some have even tuned this black humour into a business opportunity. Philipp Messinger and Bastian Ignaszewski have invented a board game based on the Berlin airport disaster. The main object of the game is to waste as much public money as possible.

I pick up a card saying some of the escalators from the train station were built too short, needing very expensive additions. "Everything on these cards," Mr Messinger says, "has really happened."

Intense attempts are now being made, Mr Dorn says, to ensure all the official permissions are obtained before the planned opening, in October 2020.