The Iraqi defector who convinced American and British intelligence services that Iraq had a secret biological weapons program with mobile laboratories now admits he made it all up.

Rafid Ahmed Alwan al-Janabi, codenamed Curveball by German and American intelligence officials who dealt with his claims, has told the Guardian that he fabricated tales of mobile bioweapons trucks and clandestine factories in an attempt to bring down the Saddam Hussein regime, from which he had fled in 1995.

“Maybe I was right, maybe I was not right,” he said. “They gave me this chance. I had the chance to fabricate something to topple the regime. I and my sons are proud of that and we are proud that we were the reason to give Iraq the margin of democracy.”

The admission comes just after the eighth anniversary of Colin Powell’s speech to the United Nations in which the then-US secretary of state relied heavily on lies that Janabi had told the German secret service, the BND. It also follows the release of former defence secretary Donald Rumsfeld’s memoirs, in which he admitted Iraq had no weapons of mass destruction programme.