Veteran Labour politician Tony Benn collapsed seconds after Tony Blair had finished his conference speech.
Mr Benn, who had been smoking his pipe while watching the Prime Minister deliver his speech on television from a cafe in the Hilton Brighton Metropole Hotel fell to the ground as he tried to enter a toilet.
He was unconscious for a few minutes but came round before paramedics arrived five minutes later.
He was lifted into a wheelchair and taken into an ambulance waiting outside the hotel.
He was joined in the ambulance by his son, International Development Secretary Hilary Benn.
Bob Deffee of the Refugee Council was one of the people who discovered Mr Benn after he had collapsed.
Mr Deffee said: "He just fainted as he tried to push the door open after Tony Blair's speech finished. We helped him to recover by loosening his tie and he was fine but we called for first aid.
"It was good that so many people were around to help him."
Fran Collingham from Coventry City Council said: "He had just finished watching Tony Blair's speech when he passed out and he collapsed on the floor and was unconscious for several minutes. He came to and sat up against the wall. Someone got him a glass of water.
"By the time the paramedics took him away he was conscious and talking. He looked a bit grey but was talking quite animatedly with the paramedics."
Paramedics working full time within the secure Island Site were alerted about Mr Benn at 3.36pm.
They were just yards away and were by his side three minutes later.
The Sussex Ambulance Service declined to identify their patient but said the man complained of feeling unwell.
An ambulance arrived outside the hotel at 4.14pm and Mr Benn arrived at the Royal Sussex County Hospital, Brighton, at 4.23pm.
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