LONDON, England (CNN) -- Reporter Andrew Gilligan who was criticized in the Hutton Report for saying the UK government exaggerated the threat posed by Saddam Hussein to justify war has resigned from the BBC.

Gilligan's report, based on an interview with weapons expert David Kelly, sparked a huge controversy last summer that eventually led to the scientist taking his own life.

The BBC confirmed on Friday that Gilligan had quit, adding "We recognize that this has been a very difficult time for him."

In a statement to the Press Association, Gilligan admitted that some of his reporting about an intelligence dossier on Iraq weapons of mass destruction before the war was wrong.

He added: "I again apologise for it. My departure is at my own initiative. But the BBC collectively has been the victim of a grave injustice."

Gilligan said he had not been forced to resign but was quitting to protect the institution he "loved."[...]

...He said the BBC's punishment was "far out of proportion to its or my mistakes, which were honest ones".

Mr Gilligan said: "This report casts a chill over all journalism, not just the BBC's.

"It seeks to hold reporters, with all the difficulties they face, to a standard that it does not appear to demand of, for instance, government dossiers."