Video report by ITV Granada Sport Correspondent Mike Hall
The family of a boy who died of a cardiac arrest during a swimming lesson are calling on the government to make defibrillators compulsory in schools and workplaces.
It's 10 years since Oliver King died, aged just 12, but his life could have been saved had a defibrillator been available.
Since his death is family set up a foundation in Oliver's name has so far delivered 5,500 defibrillators to schools and organisations across the country, saving 56 lives.
They're now calling on the government to help them save more.
It's a campaign supported by former Bolton Wanderers Footballer Fabrice Muamba, who suffered a cardiac arrest during a game in 2012.
He said watching Christian Eriksen's collapse on Saturday night brought back painful memories.
Muamba’s heart stopped beating for 78 minutes after the Bolton Wanderers midfielder collapsed on the pitch during an FA Cup quarter-final at Tottenham Hotspur in March 2012.
He told ITV News: "Like any football fan, you're in shock, you actually can't believe it.
"It's actually happening to a professional player, I'm in disbelief to be honest, how everything unfolded in front of people's faces."
"I was watching the game and I was like, 'come on, come on, come on Christian'."
He added: "This is not what we want this to end like, you know, but it was a horrible, a horrible feeling put it that way."
Describing what it was like for him during the incident, he said: "Those are the emotions that I've buried, that I bury inside me...and to actually see it happen again, it was not great."