A ballet dancer practices in the sunshine at the Southbank skatepark in London on Monday, September 17, 2018, as Storm Helene is due to bring unseasonably warm weather in London and the south east, as the low pressure draws up warm air from the south. Forecasters have downgraded warnings that Helene could pose a risk to life when it hits this week – but warned coastal communities to stay vigilant. (Photo by Kirsty O'Connor/PA Wire)

Prince William exchanges rings with his bride Catherine Middleton in front of the Archbishop of Canterbury Rowan Williams inside Westminster Abbey on April 29, 2011 in London, England. The marriage of Prince William, the second in line to the British throne, to Catherine Middleton is being held in London today. The marriage of the second in line to the British throne is to be led by the Archbishop of Canterbury and will be attended by 1900 guests, including foreign Royal family members and heads of state. Thousands of well-wishers from around the world have also flocked to London to witness the spectacle and pageantry of the Royal Wedding. (Photo by Dominic Lipinski - WPA Pool/Getty Images)

A sheep and a gentleman farmer take to the streets of London today to mark the launch the new English Countryside chapter of Farmville, Zynga's global social gaming phenomenon on March 29, 2011 in London, England. Farmville English Countryside gives players all-new crops, buildings and decorations located in the beautiful English Countryside. (Photo by Gareth Cattermole/Getty Images for Farmville)

Their Royal Highnesses Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge kiss on the balcony at Buckingham Palace on April 29, 2011 in London, England. The marriage of the second in line to the British throne was led by the Archbishop of Canterbury and was attended by 1900 guests, including foreign Royal family members and heads of state. Thousands of well-wishers from around the world have also flocked to London to witness the spectacle and pageantry of the Royal Wedding. (Photo by Peter Macdiarmid/Getty Images)

An installation consisting of a series of bird boxes is displayed in a tree in Duncan Terrace Gardens in Islington on March 24, 2011 in London, England. The boxes by artists Bruce Gilchrist and Jo Joelson of “London Fieldworks”, were designed to reflect the architecture of the Georgian terraces and flats that surround the park in the community gardens. (Photo by Dan Kitwood/Getty Images)

A Sotheby's employee holds a 110.03 carat sun-drop diamond on October 24, 2011 in London, England. The diamond is the largest yellow pear-shaped diamond in the world, and is expected to fetch between $11-15 Million USD when it is sold at auction at Sotheby's Auction house in London. (Photo by Dan Kitwood/Getty Images)

A gallery assistant holds a print of an Andy Warhol artwork estimated to fetch 1,500 GBP in Bonhams auction house on November 25, 2011 in London, England. The auction of prints of works ranging from old masters to contemporary artists takes place in London on November 29, 2011. (Photo by Oli Scarff/Getty Images)