When the time came for Paul Merson to hang up his boots, he had already enjoyed a footballing life many could only imagine. 

The former midfielder won six trophies with Arsenal, a club he made more than 400 appearances for, and represented England at both a World Cup and a European Championship. His was the kind of career aspiring footballers dream of.

But at 43 years old, sitting alone after being told he had melanoma - the deadliest form of skin cancer, which kills around seven people in the UK every day - none of it mattered.

'I thought of the times people told me, "you've lived the life and got the T-shirt,"' he tells the Daily Mail.

'And I sat there and I thought, "I haven't even lived my life…" I hoped I was only halfway through it.'

Though Merson spent decades publicly battling gambling, alcohol and cocaine addictions, being told he had cancer remains one of the scariest moments of his life.

'I remember after coming out, someone asked me, 'What did they say?' And I said, 'I can't remember,'' he continues.

'That's why I'd always say it's so important to take someone with you, because as soon as you hear that word, cancer, you just switch off.'

Now 58, Merson considers himself fortunate to be able to reflect on his diagnosis - unlike the thousands of Britons who die from melanoma every year.

And with the benefit of hindsight - and greater awareness of the disease - he can now recognise the warning signs he ignored.

First of all, he loved the sun. He often trained shirtless throughout his career and says awareness around sunscreen simply wasn't as widely recognised as it is today. 

Sun exposure - and sunbeds, too - is widely recognised as one of the leading causes of melanoma due to ultraviolet (UV) rays penetrating the skin. 

Over time, this can cause moles to develop. 

For years, Merson had noticed a mole on his back changing. Aware of what it could mean, he knew it wasn't right - but delayed getting it checked.

Even when it continued to grow - a warning sign of melanoma - Merson turned a blind eye.

But in September 2012, it became impossible to ignore.

'The mole was right in the middle of my back, so I couldn't touch it,' he says. 

'I could never feel if it was rough or anything like that. So I left it and left it. I knew it wasn't alright. I knew it was weird.

'I don't know if it's a man thing, being scared or whatever, but one day I was on holiday with my kids and I had a white T-shirt on. When I got up, there was a mark on it.

'I thought I'd sat on some chocolate, but the mole was bleeding.'

The intervention came just in time, as luck would have it. Doctors told Merson that if he had waited just another two months, the cancer would likely have spread to other parts of his body.

Within a day of receiving the diagnosis, surgeons acted rapidly to remove the mole containing the cancer, leaving him with 50 stitches on his back.

Merson admits he was fortunate to be able to seek private treatment, allowing him to deal with the disease within days of finally seeking help.

However, that didn't mean the fear went away.

Every six months, Merson would return to Harley Street in London for scans, sitting in waiting rooms alongside people who did not always receive the same good news that he did.

'You could see it on people's faces,' he says. 'Some people didn't get told it was alright this time around and it was sad, really.'

It is a time of his life that has stuck with Merson so greatly, that he is now championing a campaign by Boots and Macmillan Cancer Support to raise awareness of the importance of sun safety.

As he urges Britons to look after themselves this summer - where temperatures are expected to soar - the 58-year-old says his biggest regret is that his diagnosis could have been prevented.

It is a pertinent warning given that diagnoses of skin cancer have surged in Britain over the past decade, with cases of melanoma increasing by almost a third. There are around 19,400 new cases every year in the UK and 2,600 deaths.

In official guidance, the NHS says 'it's often possible to prevent skin cancer by being careful in the sun' and 'by using sunscreen and reapplying it regularly'.

'The frustrating thing was that it could be stopped,' Merson says. 'I just wanted to look good with my suntan.

'There's certain other cancers you get and you can't stop them and that's just the way it is, but with something like this, you can stop it.'

Just last month, the Daily Mail reported how a survey by Melanoma Focus of more than 3,000 British adults found that more than one in three admitted to never using sunscreen during the summer months.

Recent photographs of England stars Declan Rice and Jordan Pickford appearing noticeably sunburnt during their pre-World Cup photoshoot in America also caught Merson's eye.

'That's how quickly it happens,' Merson says.

'I've been in America enough times in my life and even on a cloudy day over there, UV rays come pelting through. You think, 'Oh, it'll be alright. It's not hot out today.' But they come steaming through.

'And when you've got a nose like Declan and me, you've got to be careful!'

Though delivered in jest, Merson's warning does carry a serious undertone.

New research by Boots also found that 80 per cent of adults have burnt the back of their neck in the past. More admitted they do not always apply sunscreen to their neck on a typical summer's day.

To coincide with the World Cup, the aptly named 'Back of the Neck' campaign is offering 20 per cent off Boots' Mole Scanning Service, operated by Screen Cancer, until July 19.

Clare O'Connor, Suncare Scientific Advisor at Boots, said: 'While this campaign is encouraging people to think about the back of the neck, which is a regularly forgotten area for protection, it's important not to stop there.

'Sun protection should cover all exposed skin, remembering the scalp, ears, hairline and neck, which are all often missed yet particularly vulnerable to sun damage.

'When applying sunscreen, use a generous amount of high-factor, broad-spectrum protection against both UVA and UVB rays, and reapply every two hours and always after swimming.

'Alongside sunscreen, protect your skin by wearing a hat, T-shirt and sunglasses, and spend time in the shade between 11am and 3pm.'

Merson urges people to heed the advice - just as he wishes he had done years earlier - because not everyone is fortunate enough to catch melanoma early.

'I'm more aware now,' he says. 'Every morning I put my cream on my face without fail, as well as my neck, ears and back.

'On holiday with the kids, I've probably taken my T-shirt off twice for about 15 or 20 minutes, and if I do, I'm caked up in factor 50.'