Dwain Chambers finished his chicken and prawns, slipped through the terminal, thanked the wellwishers and headed for a plane back to the big time. “There’s always someone who comes out of the woodwork,” he said as the depression and drug cocktails faded to bad memories and he launched a defence of his much-mocked Project Bolt. “And that’s where I come in.”

This is the moment of truth for the whistleblower. He says the World Championships in Berlin, starting a week on Saturday, are the biggest test of his life. Cleaned up and cleaned out — he still owes the IAAF, the world governing body, a six-figure sum of ill-gotten gains — it is a case of Berlin or bust. Fed up with living off crumbs on the B-list circuit, Chambers wants the top promoters to end their ban on former drug cheats and thinks success at that event will secure it.

“I have got over the bitterness and it’s not going to destroy me,” he said before boarding his flight to the Great Britain training camp in Portugal.

Has he contemplated quitting? “I think about it all the time,” he said. “I’m only human. Most people in my position would have. But I’m not going to go and flip burgers. That’s not what I do. When the chips are down, I pull it out and when I’m on that line for the 100 metres final on August 16, 21.35, I’m going to run. You can be sure of that.”