Documents retrieved by The Times from the ministry show that Mr Omaar wrote effusive letters to Uday al-Taie, who was close to Saddam Hussein and once expelled from France for spying.

Since the collapse of the regime he has disappeared, but his files on hundreds of correspondents, whom he screened with the Iraqi Intelligence Service, remain intact in the looted Information Ministry building.

All Western journalists were obliged to show deference to the Iraqi authorities, but Mr Omaar showed himself to be a master of the art. After one trip he wrote that the high point had been a dinner with Mr al-Taie: “After promising and promising to have dinner with you for such a long time — we finally did it. Alhamdullilah!!!!! For me, this was the main achievement of my visit.”

The tactic seemed to work. A note in Arabic on the letter suggests that it be forwarded to the visa department. Before another assignment, Mr Omaar wrote: “It’s been such a long time since we last saw each other, and I would really like to see you again. As you once said to me: Once you have tasted the waters of the Tigris, you can never forget Baghdad!!!”

Journalists working in Iraq often had to bribe and flatter the authorities to get visas and remain in the country. Those who wrote negative stories were blacklisted and those permitted to stay had to pull punches, particularly avoiding writing about the ruling family and sensitive subjects such as human rights abuses. The letters nonetheless give ammunition to the BBC’s critics.

Mr Omaar, who was nicknamed the “Scud Stud” for his vivid reports, declined to comment on the letters, but the BBC said that they showed him behaving in an entirely professional manner.

“These are the kind of letters that a journalist sends when he is building up a relationship with an individual who controls the access to allow him to report,” a spokesman said. “He is asking for something and doing so in an entirely professional manner.”

Mr Omaar was criticised for placing too much credence in official statements from Baghdad. But the BBC has defended him, saying that most viewers will have been impressed by his “courage and the cool-headed reporting” during the conflict.

His live report as Saddam’s statue in central Baghdad was pulled down was watched by four million viewers on BBC One.

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