The British journalist kidnapped from a hotel in Basra has been handed over to UK officials in southern Iraq, following his release.
Mr Brandon was videoed with his captors
Earlier on Friday, James Brandon, 23, was taken to the Basra office of radical cleric Moqtada Sadr and freed.
His kidnappers, who had threatened to kill him on a video, had treated him well once they knew he was a journalist, Mr Brandon said.
He was kidnapped by masked gunmen from his hotel room in Basra on Thursday.
A Foreign Office spokeswoman said it was "relieved" he had been freed, adding: "He is safe and well and in the hands of the British Office in Basra."
In a hastily arranged press conference after his release, Mr Brandon, from London, thanked his kidnappers.
Sporting a black eye, he said: "Initially I was treated roughly, but once they knew I was a journalist I was treated very well and I want to say thank you to the people who kidnapped me."
When asked if he could identify any of his captors, he replied: "No, they were wearing balaclavas."
During the press conference a spokesman for Mr Sadr, seated next to Mr Brandon, apologised for the kidnapping and invited him to join the Muslim faith.
"We apologise for what happened to you. This is not our tradition, not our rules. It is not the tradition of Islam," the spokesman said.
Mr Brandon's mother, Hilary Nassim, later stood on the steps of the Foreign Office in London and said it had been "a long day".
She said: "There must have been hundreds of people here and all over Iraq helping him.
"I've spoken to him on the phone and he was joking about his black eye and he is happy. I'm just glad he has been released."
The kidnappers initially demanded US troops pull out of the Iraqi holy city of Najaf within 24 hours or Mr Brandon would be killed.
They released two videos featuring the journalist on Friday.
In the first, he appeared with bandages wrapped around his head and confirmed his name and occupation while a kidnapper made death threats.
On the second tape Mr Brandon was badly bruised and sat silently while the voice of a kidnapper promised his release after intervention from Mr Sadr.
The radical cleric intervened as a temporary truce in Najaf brought an end to more than a week of heavy fighting between his men and the Iraqi-US force.
Mr Brandon was seized when gunmen dressed as policemen burst into the Hotel Al-Diafa, in Basra, and demanded to see the guest book on Thursday night.
One hotel employee told AFP news agency: "One of them said 'how dare you have foreigners in your hotel' and then they stormed upstairs.
"We then heard two shots and minutes later they were dragging the British journalist down and he was bleeding."
Mr Brandon was in Basra filing material for the next edition of the Sunday Telegraph, although he also worked for The Scotsman and The Independent
Con Coughlin, associate editor of the Sunday Telegraph, said the paper had taken the death threat "very seriously from the moment it was issued".
He said the paper had been "in constant contact" with Mr Brandon before he went to Basra, who had given assurances that he was properly prepared for the trip.
More than 70 foreigners have been taken hostage in Iraq in recent months.
About 20 are still being held and at least eight hostages have been executed.