An 82-year-old activist thrown out of the Labour party conference for heckling Jack Straw has returned to the venue to a hero's welcome.
Walter Wolfgang, from London, was cheered as he held up his security pass - confiscated by stewards on Wednesday.
He said a "small mistake" had been rectified - unlike the "big mistake we made in invading Iraq".
Tony Blair earlier apologised for the incident, which came after Mr Wolfgang shouted "nonsense" during the speech.
The prime minister told BBC Breakfast: "I am really sorry about it, it shouldn't have happened."
Labour said Mr Wolfgang could return for the conference's final day provided he did not cause further disturbances.
A Labour member of 57 years' standing, Mr Wolfgang told reporters that some people in the party had been "irresponsible in hiring heavies". The party needed to get back to a culture which was " open to argument", he added.
Speaking earlier, Mr Blair said of the stewards: "It is difficult for them when someone is interrupting someone's speech, but it should be handled sensitively, particularly with an older person."
He told the BBC there had to be better training for stewards in the future.
Asked if he would apologise face-to-face to Mr Wolfgang, the prime minister said he did not expect to meet him, adding: "I can't do anything more than apologise profusely."
After being ejected Mr Wolfgang's pass was seized and he was detained under the Terrorism Act when he tried to re-enter the conference on Wednesday.
Questioned about why Mr Wolfgang had been briefly arrested under the Terrorism Act, Mr Blair said: "My understanding is that his delegate's credentials showed he had been ejected before and he had to wait while that was checked out."
Shadow home secretary David Davis said civil liberties and security should not be confused.
Fellow Tory leadership campaigner David Cameron described the incident as "one of those moments which lays bare the full absurdity of the Orwellian New Labour project".
He said the use of the Terrorism Act in preventing Mr Wolfgang's return was "profoundly depressing".
Liberal Democrat president Simon Hughes told BBC Breakfast: "Here's a conference with the foreign secretary tackling some of the most controversial issues of the day and people aren't allowed to stay in their seats if they shout any protest, even restrained protest.
"It just seems to me that it's an attitude question about authority and authoritarianism."
Scottish National Party Leader Alex Salmond said Labour could "censure their delegates but they won't be able to gag the people".
"There was a time when politicians could deal with a few hecklers," he added.
Labour Party Chairman Ian McCartney apologised, but also said Mr Wolfgang had nevertheless misbehaved.
"He was asked to calm down and be quiet, he could have taken that opportunity and watched and listened to the debate but he chose to continually disturb the event and so we removed him."
Mr Wolfgang, who escaped Nazi Germany in 1937, is a member of the Stop the War Coalition.
He told BBC Two's Daily Conference Live programme: "These two toughies came round and wanted to manhandle me out.
"I said: 'Do you want me to leave? I will leave, you don't need to manhandle me.' Physically, I am not too well, so I said I would follow them.
"Most of the Labour Party stewards are very nice people. One or two people lend themselves to this nonsense."
Erith and Thamesmead constituency party chairman Steve Forrest, who was sitting next to Mr Wolfgang, was also thrown out after complaining about the stewards' response.
Sussex Police stressed that Mr Wolfgang was not arrested or searched at any point "during his brief interaction with the police officer".