Most people "underestimate the sun" and the irrevocable damage it can do to skin, a 21-year-old skin cancer survivor warned Good Morning Britain.
Kelli Cooke from West Sussex was diagnosed with malignant melanoma at 19, despite always being vigilant with sunscreen and wearing factor 30.
She is now in remission but said she had to "be really careful" and carried suncream with her "all the time".
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The teenagers, aged 19 to 15, appeared in custody at Westminster Magistrates' Court on Saturday, supported by their families.
Labour must "broaden its reach" in order to win votes off the Conservatives, deputy leader Tom Watson has said.
Nicola Sturgeon said the London mayor's comments that likened Scottish nationalism to racism were a sign of 'desperation'.