The government is warning that the NHS will be under even more pressure this weekend as temperatures soar, so looking after yourself in the sunshine is crucial.

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But how much do you know about the science behind sunburn… and how to prevent it?

What is sunburn?

While we all know what sunburned skin looks like – red and sore – it might not be so clear what is happening underneath the skin.

“Essentially, it’s inflammation,” said Dr Rachel Abbott, a consultant dermatologist who specialises in skin cancer for the Cardiff and Vale University health board.

“It’s triggered by ultraviolet radiation, primarily UVB but also by UVA.”

Ultraviolet radiation is carcinogenic and when it is allowed to penetrate the skin, it triggers an inflammatory reaction, said Dr Abbott.

Histamines – chemicals produced by the body’s immune system – and prostaglandins – compounds that help the body deal with injuries and illness – are released as your body begins reacting to the damage.

Although the inflamed, red, itchy skin will fade, those carcinogens will do permanent damage to your DNA, according to Dr Abbott.

“The redness and pain can be managed symptomatically, but that DNA damage is permanent,” she said.

“We’ve all got DNA repair mechanisms in our bodies. But this is why we’re seeing such a massive increase in skin cancer, because [as we get older], the battle between the DNA damage and the skin cells becomes more than the immune system can cope with.”

Since the early 1990s, the number of skin cancer cases in Britain has more than doubled and last year, the number of cases was predicted to hit an all-time high of 20,800, according to Cancer Research UK.

The cancer charity partially attributed the rise in cases to older groups of people knowing “less about the dangers of tanning in their youth”, who “may have taken advantage of the cheap package holiday boom from the 1960s”.

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This would lead to increased sun exposure and more damaged DNA, increasing the risk of skin cancer further down the line.

The ‘most effective’ protection (and it isn’t suncream)

There is currently no conclusive treatment to deal with the DNA damage caused by sunburn – although Dr Abbott said there is “exciting” work being done in that area.

Instead, the way to stop yourself from sustaining long-term damage is to protect yourself from UV rays.

“A lot of people associate temperature with the heat of the sun, whereas actually it’s the UV index that’s the critical thing. And that usually peaks around midday,” said Dr Abbott.

Contrary to what some may think (or hope), suncream should be a last resort.

Shade “is the most effective thing”, she said, but if you have to be out in the sunshine, “obviously we recommend hats, clothing and then sunscreen”.

“It is a last resort for those areas that you can’t cover up with clothing and hats, and sunglasses.”

The cancer care charity Macmillan recommends a suncream with a sun protection factor (SPF) of 50, or at least 30, and to reapply it regularly.

“There is no such thing as a safe suntan,” advises the charity.

It also recommends using around six to eight teaspoons of suncream for an adult – one teaspoon for each limb, one for your chest, one for your back and one for your head and neck.

Prince William has had a lot to say this week, attending three events about the environment as part of London Climate Action Week and giving three speeches.

But I wouldn’t be surprised if you haven’t really heard what he had to say. The eyes of the world have, understandably, been elsewhere.

Conflict, not the climate crisis, has been the primary focus of world leaders and continues to be – a problem you could say for William and all those trying to whip up momentum ahead of COP30 in Brazil, with only four months to go until the UN’s climate conference in November.

It was William and his team who specifically convened a meeting at St James’s Palace on Thursday with the Brazilian ministers in charge of the summit and indigenous leaders from other parts of the world.

With Ed Miliband, the secretary of state for energy security and net zero, just a few seats away, William made a call to action, saying: “We’ve made bold commitments: to halt deforestation, restore ecosystems, and protect 30% of land, sea, and water by 2030.

“But these goals will remain out of reach unless we move from promises to action – grounded in respect, equity, and shared responsibility.

“Looking ahead to COP30 in Belem and beyond, we must act with greater ambition and deeper collaboration. This is a moment for courage.”

When I put it to a palace source that maybe it all feels a bit futile in the current climate, with attentions firmly elsewhere, I was told there is “no change in course” – the prince always has and will continue “to use his platform to spotlight the need to restore the planet”.

In the past, we’ve been more used to his father being more vocal.

The King’s involvement in London Climate Week was more fleeting, albeit involving a handshake with a giant gorilla puppet, and a discussion with the Brazil delegation in which he hinted that he would love to attend the summit in November, saying: “It’s fitting it all in.”

Attendance by either the King or the Prince of Wales hasn’t been confirmed yet, although it’s looking likely William will go. He told one person this week: “I’ll be in the area”, with his Earthshot Prize being held in Rio in the days running up to the climate conference.

But in the coming months, we do now know that father and son will be meeting with one key player, who has certainly voiced very different views on the severity of the climate crisis.

This week, it was confirmed that Donald Trump’s full state visit to the UK will go ahead later this year, likely in September.

His potentially disruptive presence when it came to the climate debate was hinted at on Tuesday, in front of Prince William, during a speech by former New York mayor Mike Bloomberg.

Mr Bloomberg, a global adviser to Earthshot Prize, said: “There’s a good reason to be optimistic, lots of problems around the world, America has not been doing its share lately to make things better, I don’t think. Nevertheless, I’m very optimistic about the future.”

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The King and Prince William have worked in this environmental sphere long enough to weather the frustrations of other distractions, a lack of interest or momentum.

I’ll never forget in 2015 ahead of COP21, when Islamic State and Syria were dominating the news agenda, Prince Charles told me very firmly that of course there was a link between the civil war in Syria and climate change.

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He said there was “very good evidence indeed that one of the major reasons for this horror in Syria was a drought that lasted for about five or six years, which meant that huge numbers of people in the end had to leave the land”.

“It’s only in the last few years that the Pentagon have actually started to pay attention to this,” he added at the time. “I mean, it has a huge impact on what is happening.”

But as a family, they know how much their global profile and ability to get people in the room can help attract attention that others simply can’t.

It’s easy to be sniffy about that convening power, but as one delegate at an Earthshot event put it, they have an ability to “bring people together not around politics but purpose”. And in a currently noisy, fractured world, it feels like that is needed more than ever.

Pulp tried to quash the rumours, Robbie Williams was happy to fuel them – sharing a picture of a blue plaque in his name apparently slapped over a famous Glastonbury sign, before seemingly backtracking.

“30 years later…” he captioned his first social media post early on Friday morning – a reference to his headline-grabbing attendance in 1995.

This was the year Williams was famously pictured partying with Oasis‘s Liam and Noel Gallagher, shunning the boyband shackles with bleached-blonde hair and a blacked-out tooth. The writing was on the wall, and the announcement of his departure from Take That came just a few weeks later.

At Glastonbury this year, is the writing quite literally on the wall for a comeback?

Well, maybe not. A few hours after his post, Williams shared another, less cryptic message to say he would not be performing, along with his list of recommended acts to go and see – The 1975, Busta Rhymes, Charli XCX, Self Esteem and Reverend And The Makers, if you’re interested.

Is he bluffing? Double-bluffing? Who knows, but along with celeb spotting and mud, if there’s one topic of conversation that makes headlines when it comes to Glastonbury, it’s speculation about secret artists. Williams has got everybody talking.

Even before his posts, the Let Me Entertain You singer was among the artists rumoured to be performing secret sets this year, along with Pulp and Haim. Lewis Capaldi and Lorde too, with both “TBA” acts turning out to huge crowds on Friday.

In recent years, these surprise sets have turned into some of the event’s most memorable moments – think Foo Fighters as “The ChurnUps” in 2023, Pulp’s comeback in 2011, and Lady Gaga treating fans to a small performance in one of the festival’s after hours areas, Shangri-La, in 2009.

Franz Ferdinand, famous for hits including Take Me Out and Do You Want To in the mid-2000s, were the first to do it back in 2008. This was actually due to Pete Doherty’s band Babyshambles pulling out last-minute, but the approach to announcing the switch was, at the time, a novel one.

While officially, the act was “TBA”, frontman Alex Kapranos wasn’t great at keeping the secret, worried people might not turn up. He and bandmates handed out fliers, and word spread.

“We played on the Park Stage and we thought, ‘nobody’s going to know we’re playing’,” Kapranos told Sky News ahead of a return performance on Friday. “It actually ended up being one of the most amazing gigs we’ve ever played, people were so up for it and going crazy.

“We weren’t keeping it secret. We were walking about like, ‘we’re playing later on, check it out’. We’re a band from Glasgow called Franz Ferdinand.”

These now not-so-secret performances have become bigger and bigger as each festival rolls around, with leaks making headlines in the run-up to the event.

Providing handy tips and hints – and often eventually confirmation, just in time for fans to be in position – is the Secret Glasto team. They have no official ties to Glastonbury, but over the years have become a reliable source of information.

The account’s founder, who now works in a team of six, spoke to us on site – incognito, of course.

“We’ve got our own sources and we can start checking things because we’ve now had enough years that we can check in with several people,” he said. “And they trust us because we are quite sensible with when we time announcements, which I think is the key thing.”

Sometimes acts themselves will confirm, they said. Their success rate for predictions is “in the low 90%” – but dragged down mainly by inexperience in their first year, which was 2014.

Capaldi’s comeback yesterday, two years after struggling on stage at Glastonbury in 2023, was a special moment.

“It was really, really heartwarming to see him get back up,” Secret Glasto said. “There was such goodwill in the crowd and it was just magical. It’s just what secret sets should be about.”

On Saturday evening, a non-existent act called Patchwork have a pretty important billing just before Raye and then headliner Neil Young on the Pyramid Stage.

Pulp keyboard player Candida Doyle dampened rumours by reportedly saying in an interview earlier this month Glastonbury “weren’t interested” in booking the band.

But is this true?

“It happens a few times,” Secret Glasto said, of artists maybe telling little white lies to keep the secret for as long as possible. “They’ve got to keep the suspense somehow…

“Sources that we got for Pulp were really, really strong. It’s just so exciting for us, for the whole team. This is the most exciting secret set that Glastonbury’s ever done.”

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It’s a fine balance – not spoiling the surprise but giving fans enough time to get where they want to be. When a festival is this big – home to around 200,000 people over the weekend – at a lot of stages, fans need to be in place early.

“The point is to always make sure people can get to the set if they wanted to.” But if a huge artist is going to surprise fans on a very small stage, sometimes they have to keep schtum for safety concerns over huge crowds. “Sometimes we’re like, we can’t print this.”

So, will Williams be playing? The rumour is that he could be joining his mate Rod Stewart, who is performing on the Pyramid Stage in the “legends” slot on Sunday.

“Robbie Williams entered this area without accreditation, authorisation, or alignment with prevailing taste,” according to the blue plaque in his social media tease, of his attendance in 1995. “His presence was uninvited, unofficial and ultimately inevitable.”

In his candid documentary series, and biopic Better Man, both released last year, Williams has been open about his struggles with fame and imposter syndrome, and how as an artist known for pop he craved respect from those seen as more credible at a time when indie music reigned.

Officially this year, there is no Robbie Williams on the line-up. Unofficially, who knows? But 30 years since his partying with the Gallaghers, pop music is embraced – and there would be a lot of love for the star if he did make an appearance now.