The father of a Welsh soldier who died in Iraq said his protest outside the Labour conference was to force Tony Blair to talk about his son's death.
Reg Keys said he had to time his protest to avoid the security
Reg Keys, from north Wales, climbed on to a pylon on Brighton seafront and put a noose around his neck.
He said he had no intention to kill himself, as the noose was meant to stop someone from pulling him down.
His son, Lance Corporal Thomas Keys, 20, was one of six Red Caps killed last year by a mob of more than 400 Iraqis.
Mr Keys, from Llanuwchllyn, near Bala, said he had spent hours practising how to make a hangman's knot for the protest on Tuesday.
He added that he had put an extra knot in the noose to make sure he would not be strangled if he had fallen off.
Mr Keys climbed the pylon a few hundred metres from the conference hall and was there for around 40 minutes before coming down.
He said that he timed his approach to avoid the security along the seafront during the Labour conference.
He said: "I had to pick my moment, there were helicopters overhead and armed police on the rooftops.
"I could just seen a chink in the armour and I thought I would go for it.
Lance Corporal Thomas Keys was killed in Iraq by a mob
"I had a banner rolled up on my back and I was concerned because I thought that, from a distance, it might look like a rifle and I would get shot off."
He said his aim was to make a point about the war in Iraq - and to make Tony Blair apologise "for betraying my son and other servicemen".
He said: "Blair sent my son to war, telling them they were going to fight WMDs.
"If Tom had been killed by a weapon of mass destruction, I would not be saying anything now.
"When I waved goodbye to Tom, he had his chin up high thinking he was going to defend his country."
Mr Blair, in his conference speech, said: "I can apologise for the information that turned out to be wrong but I can't sincerely apologise for removing Saddam."
Mr Keys said his threats during his protest to kill himself were only for effect and to stop the police from trying to pull him down.
Mobile phone number
He said he gave a policeman his mobile phone number and asked for it to be passed to Mr Blair so the Prime Minister could call him to discuss Thomas' death.
He said: "We have met before, he knows who I am.
"All it would have taken was for him to ring me and say 'Reg, come down, we'll talk about it'.
"Had I been genuinely disturbed, he couldn't have cared less."
Mr Keys said police spoke to him and cautioned him after the protest.