The family of a man who remains in a serious condition after suffering a heart attack on the hottest day of the year have praised the off duty nurse and doctors who saved his life.

Darren Norman, who would have celebrated his 44th birthday today, had been walking with partner Trish Crisp and two grandsons, aged one and six, in Eaton Park when he collapsed.

After he stopped breathing for 20 minutes, Mr Norman is still at the Norfolk and Norwich University Hospital but is improving.

His dad Mick, 69, said there were 'no words' to thank the medical staff who came to his aid and saved him from permanent brain damage - or worse.

'They were just having a little stroll when Darren went down with a pain and collapsed,' he said. 'Trish cried out for help and this woman who was a nurse came running over and started CPR straight away.

'At the same time there was a doctor who was out jogging and stopped to chat to another doctor when they saw this woman doing CPR, so they ran over to help. It was bizarre and very, very lucky.

'Those are the critical moments. They said had it not been for the first nurse starting CPR he would not be here today.

'We can't say how grateful we are to them, it is beyond words. All the family really just want to thank them for saving his life. It may just be a job to them, but what they did for us is unbelievable.'

Mr Norman said his son is on the mend, and doctors have told the family there would be 'minimal to no brain damage'.

'He is now waking up and is starting to recognise people,' he said. 'He gave my hand a little squeeze when I was in, and he is off sedation.

'The doctors are very optimistic. That is only because the nurse started CPR so soon. 'It is incredible, and I have never known anything like it.'

The East of England Ambulance Service said the incident occurred at 1.11pm on Saturday.

The first paramedic was at the scene within three minutes of the initial call. When they arrived two off duty doctors were already helping.

Mr Norman was not breathing when paramedics first arrived, but they managed to resuscitate him at the scene.

He was taken to the Norfolk and Norwich University Hospital by land ambulance.