It is no exaggeration to say Britain is in the grip of a skin cancer crisis, with cases reaching record levels.

Melanoma – the deadliest form – is at an all-time high, with nearly 21,000 Britons diagnosed every year. And it's a trend showing no sign of slowing.

With scorching summers set to become the norm in the UK, cancer specialists warn cases could climb to 26,500 a year by 2040. Meanwhile, there are around 200,000 non‑melanoma skin cancers treated each year – with numbers having more than doubled since the 1990s.

The increase in skin cancer cases largely reflects the UK's growing and ageing population, Cancer Research UK – which carried out the analysis – said. 

But, according to the charity, the vast majority of these cases are preventable.

The warning comes n the midst of a UK heatwave, with Met Office forecasters issuing a rare red weather warning for Wednesday and Thursday indicating 'a risk to life for even the healthy population.' 

So, with temperatures expected to reach sweltering highs this week – exceeding 39C in some parts of the country – how can you minimise your risk of the deadly disease? 

And what are the tell-tale signs and symptoms everybody needs to be aware of?  

Watch out for white patches and disappearing moles

Most melanomas are spotted because they appear as a new mole, or a change in an existing one – usually in areas exposed to the sun, says Dr Christopher Rowland Payne, consultant dermatologist at The London Clinic.

But a mole that shrinks or even disappears can be a far less obvious – and often overlooked – warning sign.

'Amelanotic melanomas may appear pink, or essentially clear and colourless, making them incredibly difficult to spot,' Dr Rowland Payne explains.

This can delay diagnosis, with potentially life–threatening consequences. When caught early, melanoma is almost always curable – but it becomes far harder to treat over time.

To help detect these more unusual cases, he advises checking your skin regularly for any subtle changes – including in moles you already have.

'Dandruff' could a be a sign of something sinister

Skin cancer can develop anywhere on the body – but it is often hardest to detect on the head and scalp because it is out of sight.

While many people remember to protect their face from harmful UV rays, the scalp remains one of the most overlooked – despite being highly vulnerable to sun damage.

Persistent tenderness, redness around the hairline, or even what seems like stubborn dandruff should not be dismissed, experts warn – particularly if symptoms do not improve.

'It's not uncommon for people to burn along their parting, but many don't notice until it starts to peel,' Dr Rowland Payne explains.

'By then, the damage is already done.'

The problem is that this can easily be mistaken for a dry scalp or dandruff, when in reality the skin may be shedding as part of an inflammatory response triggered by sun damage.

While dandruff itself is not a sign of skin cancer, a persistently flaky patch in one area can be.

Key warning signs include large or uneven flakes, discolouration of the scalp, or bleeding.

For this reason, it is worth spending a few extra minutes protecting these areas – applying sunscreen along your parting and wearing a hat, Dr Rowland Payne advises.

Don't dismiss scabs on the scalp 

Dry, scaly patches of sun-damaged skin – known as solar keratoses – are not always cancerous, but they carry an increased risk of developing into skin cancer.

'Older bald men who have scabs on their scalps should really have these lesions checked by a doctor,' Dr Rowland Payne says.

'They may seem harmless, but any solar keratoses should prompt a trip to the doctor – especially if they are itchy, bleeding or sensitive.'

Sun spots can be harmless – but watch for changes

Most sunspots are benign, but in some cases they can signal lentigo maligna – a slow–growing form of melanoma.

They typically appear as blotchy patches on the face, ears or neck.

Look out for asymmetry or areas of darker pigment within lighter patches.

Black lines or bruising under the nail should not be ignored

'A black mark under the nail is usually harmless, but melanoma can appear anywhere on the hands or feet – including the soles or beneath a nail,' says Dr Rowland Payne.

This type of cancer – known as acral melanoma – is more common in people of Black or Asian heritage and can appear on the palms, soles, or under the nails.

As a result, it is often detected at a much later stage.

A new bump on your eyelid could be a problem

Eyelid cancers – including basal cell carcinoma – are relatively uncommon, but they do occur, particularly with cumulative sun exposure.

Between five and ten per cent of all skin cancers occur on the eyelid. Common warning signs include a smooth, shiny or waxy bump – or one that is firm and red.

A flat, skin-coloured lesion that resembles a scar can also be a tell–tale sign. Most of these cancers develop on the lower eyelid.

'We all know sunglasses help protect our eyes from the sun, but they can also shield the eyelids – an area we often miss with sunscreen,' Dr Rowland Payne says.

Pink or orange tan could signal damage

There is no such thing as a safe or healthy tan. Tanning is caused by UV exposure, which triggers the skin to produce melanin in an attempt to protect itself from further damage.

Even people who tan easily may be at risk, so it is worth paying attention to the tone of your tan, Dr Rowland Payne says.

'People who tan well are often lulled into a false sense of security,' he explains.

'This so–called 'ability' draws them into the sun, but in reality they may be repeatedly damaging their skin.

'Pay close attention if your tan has a pink undertone, or if your skin becomes dry after time in the sun – both can be signs of damage.'

The bottom line: Avoid sunburn and wear SPF

'We do not want people to stop enjoying themselves or stay indoors, but as temperatures rise we need to be more mindful of how long we spend in the sun,' Dr Rowland Payne says.

Just one bad sunburn in childhood or adolescence can more than double the risk of developing melanoma later in life, according to Melanoma Focus.

'Sunburn causes DNA damage, which not only increases the risk of melanoma but also suppresses the immune system that helps keep developing cancers in check,' he says.

'If you get burnt, you are effectively taking a double hit.'

To reduce your risk, NHS guidance recommends limiting time in direct sunlight – especially during the middle of the day – and applying sunscreen regularly, with at least SPF 30 and a four or five-star UVA rating.

And even if you have already been caught out, it is never too late to start protecting your skin.