text: Hollie Tillbrook, 17, was saved by two off-duty police officers when she had a heart attack in Basildon, Essex . A teenager battling bulimia who 'died' on the street from a heart attack was saved by a pair of off-duty police officers who gave her CPR. Hollie Tillbrook, 17, was out with her boyfriend in Basildon's Festival Leisure Park, Essex, when she suddenly collapsed. Doctors believe her potassium levels had plummeted to such a low level that her heart completely stopped. But luckily, two officers, believed to be from the Met Police, rushed to her side and gave Hollie life-saving CPR until an ambulance arrived. She was then rushed to Basildon hospital, where she was put into an induced coma. But the teenager then made an unexpected recovery which stunned medics. She is now recovering at her home in Leigh, Essex, despite her mother Denise Bennett being told to expect the worst. The family are now trying to find the police officers who saved Hollie so they can thank them in person. Hollie said: 'I don't remember much about what happened that day but I owe the doctors and the off-duty officers everything. 'I feel very tired still and I know I have a long recovery ahead. It's been really horrible but I am so thankful to be alive.' Ms Bennett added: 'I would love to be able to meet the police officers who saved my daughter's life and for them to get in touch . 'I really want to thank the two off duty police officers that saved my daughter's life. They are just absolute heroes. 'And also the critical care team at Basildon Hospital - the treatment she received there was brilliant.' The drama unfolded while Hollie was waiting outside the Chiquito's restaurant while her boyfriend Gary Hobbs went to park his car. When he came back, he found Hollie laying on the floor with a crowd gathered around her. Ms Bennett then received a phone call, telling her what had happened. The 17-year-old, who suffers with bulimia, had collapsed because she had a dangerous level of potassium in her body. She is now recovering at home with her mother Denise Bennett (right) Humans need potassium in higher amounts than any other mineral. Adults need around 3,500mg in their body per day. Potassium plays a fundamental role in maintaining the fluid and acid/alkaline balance of the body. It is vital for the transmission of nerve impulses and helps the heart to beat regularly. It also counterbalances sodium in the body, and is known to help lower blood pressure. To get enough you need to eat plenty of fruit and vegetables, which are especially good sources because they also provide a low level of sodium. The Dietary and Nutritional Survey of British Adults (HMSO 1990) showed that the average intake of potassium is 3,187mg in males and 2,434mg in females. Compared with the daily recommendation of 3500mg intakes they are therefore low. People most at risk of marginal potassium include the elderly, athletes and manual workers who sweat out a lot of potassium and people taking certain diuretic drugs. Heavy coffee and alcohol drinkers may lack the mineral and should try to increase their dietary intake. She said: 'Fortunately a young bouncer working at the park had the presence of mind to take her phone and ring me. 'He said to me "your daughter has collapsed and is receiving CPR". I asked if she was responding and he just went quiet and said "no". The drive from Leigh to Basildon was awful. It was terrifying.' Hollie was transferred to Basildon Hospital where doctors told Ms Bennett that her heart had stopped. She had technically died for a short time, they said. The teen was then put into an induced coma. Doctors told Ms Bennett to return in the morning but to prepare for the worst. She said: 'I went home to Hollie's bedroom and was just clutching the coat she had been wearing. I was crying and crying.' But, the next morning, doctors began to bring Hollie out of the coma and she started to breathe on her own. Five days later she was allowed home. Ms Bennett said: 'I really want to warn other young people about the effects of bulimia. 'I know it is an illness but it is beyond my comprehension why these kids do this. It is not a game. It can have life-threatening consequences.' Hollie suffers from chronic fatigue syndrome (CFS), which her mother believes caused her to become depressed and develop bulimia. Doctors believe that Hollie had been so sick that her potassium levels had dropped to a dangerous level.
target: Hollie Tillbrook's heart momentarily stopped after she fainted in Basildon .
  But two nearby officers thought to be from the Met rushed to give her CPR .
  Mother Denise Bennett was told to expect worst, but Hollie unexpectedly woke up from her induced coma .
  The family now want to try and find the off-duty officers who saved her life .