By Gemma Strong Prince William and Prince Harry will take part in an award ceremony together to honour their late mother, Princess Diana, tonight. William will attend the Diana Legacy Awards at the Science Museum in person to deliver a short speech to mark the charity’s 25th anniversary. Harry, meanwhile, will meet award winners virtually after the ceremony when he speaks to them from his home in California – but only once his brother has left. The gulf between the two princes has never been wider – and it’s something that King Charles tried to address shortly after the death of his own father…