If there is one day Peter Kilfoyle will never forget, it is Saturday, 17 June, 2006. It was the day he suffered his second heart attack. He survived.

The sun was beating down on Liverpool and the Labour MP wanted to spend the day, a week after his 60th birthday, in his garden mowing the lawn and planting a small tree. Dressed in a scruffy pair of trousers he started to dig, but the ground was so dry and cracked in the heat his metal spade bent in half as he drove it into the soil.

'That was when it started,' said Peter last week, sitting in his tidy London flat, minutes from Westminster. 'I felt this sensation across my chest and shoulders. I would describe it not as pain but as discomfort. I felt restless.'

Peter knew he had experienced the same sensation once before, while he was driving along the M40, heading north from his Westminster office to his constituency in Walton, Liverpool. 'I just pulled over and let it pass, then carried on driving,' he said, not realising how serious it was.

This time the feeling did not abate. Eventually he decided to drive himself to a local hospital. 'I knew something was wrong but I didn't know what,' he said. 'I thought they might send me away with some paracetamol. My wife wanted to come with me but I said, "No, you don't want to hang around." That was how lightly I took it.'

It took another 15 minutes to reach the Royal Liverpool University Hospital and when he got there he had to walk up a hill to get to A&E. All the time the strange sensation that had spread across his upper body continued. It did not take long for a cardiologist to tell him that he had just suffered a heart attack - and that it was not his first. 'Just think, you are one of the lucky 50 per cent,' the doctor told him. 'Fifty per cent of people who have heart attacks do not make it this far.'

But Peter has not just survived, he has transformed his life. He knows, without any doubt, that it was his heavy drinking, smoking and eating that led to the attack and that is why he now walks four miles each day, avoids fattening food, drinks in moderation and never touches a cigarette. He has not weighed himself but his clothes are baggier now and set to become more so this week.

Yesterday, little more than a year after he suffered the heart attack, Peter set off from a tranquil Nicaraguan fishing village on a 140-mile trek across the Central American country to raise money for the British Heart Foundation and the Peace and Hope Trust, a local charity. It is a trip he would never have dreamt of before.

Peter knows how lucky he is to have had that second chance. Each year, around 230,000 people in the UK suffer a heart attack, one every two minutes, and tens of thousands never make it to hospital. Even he thought twice about going in.

Speaking the day before he flew out to Nicaragua, Peter told how, lying in hospital hours after the heart attack, the only thing that ran through his mind was what had happened to his close friend Mike Carr, who became a Labour MP, then died 57 days later.

'He was an MP for eight weeks and he died of a heart attack after being sent home from hospital,' said Peter, taking a deep breath and dropping his head. 'Mike Carr was an MP for Bootle and I'll never forget that night because they said it was angina and sent him home and then he had another heart attack, which killed him within hours.'

Instead, Peter was quickly taken for an angiogram to assess the health of the arteries surrounding his heart. 'That was the hardest thing for me personally to face, because I was completely conscious,' he said. 'They put this tube through an artery right into my body and then released a fluid that enabled them to do a scan on my heart. The results showed that I needed a quadruple bypass urgently.' Six weeks later Peter went in for his operation.

Sitting at the dining table in his flat next to a picture of his daughter, Amy, on her wedding day, Peter lifted up his arms to reveal thin red scars running across his skin. He pulled at his shirt and said: 'They saw through your breastbone, peel you open and go to work on you, a bit like being a butcher, I suppose.' When he first woke up Peter said he was 'high' to realise he was still alive and started joking with the medical staff. His surgeon, Aung Oo, later said: 'Typical politician - he wouldn't shut up.'

Peter has nothing but praise for the doctors who helped him through his rehabilitation, but not all get the same standard of care. A BHF report this summer revealed that patients faced a postcode lottery after suffering a heart attack, with three out of five failing to gain access to the rehabilitation they needed, such as an exercise programme, advice on lifestyle and counselling. Some were too nervous to get active again and others were dying prematurely, it concluded.

Not so for Peter, who was given the all clear last week for the tough trek he has now started. 'I know there are people out there who believe that, once they have a heart problem, they are an invalid for life,' he said. 'But it just isn't like that with modern surgical and rehabilitation techniques.'

During his rehabilitation, Peter and three other men talked to a cardiac nurse about lifestyle. 'I got cheesed off with these blokes whingeing about why this had happened to them,' he said. 'I told them, "I am in here because of one person - me. Nobody asked me to smoke all my life, nobody asked me to drink all my life, nobody asked me to indulge myself with fatty foods."'

Peter pointed towards the House of Commons and described his unhealthy lifestyle in what he called the 'house of fun'. Four days a week he could sit down to a rich lunch and go to two receptions in the evening, all the time smoking up to 40 cigarettes a day.

'I've been in full-time politics now for 20 years and you do spend a disproportionate amount of time sitting around, blowing off about every subject under the sun while stuffing your face with assorted pastries and downing the odd drink or two,' said Peter. 'You can extrapolate from that into business, into all sorts of professional lifestyles where people sit around, don't get enough exercise and eat and drink the wrong things. I had done no meaningful exercise since I came into full-time politics and I've smoked since I was a kid - 40 years.'

The heart attack forced him to finally give up smoking: 'If the choice is between having another heart attack, potentially fatal next time, and having a cigarette you'd have to be a total cretin not to see what the choice is. And even my worst enemies will tell you I am many things, but I am not a total cretin.'

He is also eating more healthily, passing on the lunches and receptions in Parliament and drinking in moderation. 'We are all allowed one poison and the medicinal value of mother's milk, aka Irish whiskey, far outdoes any damage,' he jokes. 'Seriously, I have spoken to doctors and I am not saying you should drink to excess, but the odd glass of red wine or whiskey does not do any harm.'

On his Central American trip, he will cover 10 to 15 miles a day for a fortnight. He will be accompanied by son Patrick, son-in-law Jon Gill, who is a nurse, and fellow MP Greg Pope.

'I am hardly going to indulge in contact sports after my chest has been all stitched up, am I?' Peter said. 'But exercise will do you the world of good.'

Those who have seen Peter sitting in Westminster bars drinking and smoking may be surprised by the transformation. 'Ricky Tomlinson is a friend of mine and he has just been told he has to have the same operation. It is amazing how many people of all age groups are getting this. I don't want to sound like a proselytiser for good health causes, but unfortunately I am because of my own experience.'

The long march

· For more on Peter Kilfoyle's trek across Nicaragua, shown above, go to peterkilfoyle.com

· For information on heart disease, log on to the British Heart Foundation's site at bhf.org.uk

· Peter Kilfoyle is also supporting a local charity in Nicaragua, the Peace and Hope Trust peaceandhope.org, which supports agriculture and education and offers disaster relief.