The heartbroken father of a soldier killed in Iraq threatened to hang himself off the West Pier yesterday.

Reg Keys climbed 30ft up a radio mast and tied a noose around his neck outside the conference.

He said he would jump unless Prime Minister Tony Blair phoned him and apologised for the death of his son Thomas, 20, who was one of six troops killed by an Iraqi mob in June. Police tried to coax him down and firefighters and a rope rescue team were put on standby.

A crowd gathered and applauded Mr Keys as he yelled angry messages for Mr Blair, who was delivering his conference speech at the Brighton Centre across the road. The centre was surrounded by thousands of pro-hunt demonstrators.

He waved a banner that read: "Blair lied while 65 troops died. Troops out".

Dressed in a smart grey suit and red tie, he faced the Brighton Centre and shouted: "Mr Blair, you have ten minutes to phone me and apologise for lying to my son and the nation about sending us to war or I jump.

"My life is over anyway, I don't care. I am going to hang myself in front of your conference. We'll see how that goes down around the world. I want an apology for the life of my son. Why did he only have 50 rounds of ammunition? He was sent like a lamb to the slaughter with his five comrades."

Mr Keys has become a vociferous anti-war campaigner since the death of his son, who was a Lance Corporal in the Royal Military Police.

He and his colleagues were killed in a police station, Majar el-Kabir, 120 miles north of Basra, after being surrounded by more than 400 protesting Iraqis.

He was shot 31 times by a mob protesting against alleged heavy-handed British tactics.

A Special Investigation Branch investigation into the incident has been launched but Mr Keys said he had little faith in the process. He yelled: "We went to war for oil, not weapons of mass destruction or regime change."

He eventually removed the noose and climbed down after an hour. A tearful Mr Keys gave an impromptu press conference before being taken away in an ambulance.

He said: "I staged this demonstration because Tony Blair sent my son to war for weapons of mass destruction.

"We believed him and my son went with his head held high. It proved to be a lie. My son died because Blair lied to him. I think he owes us an apology."