Visitors to Westminster Abbey are to be allowed to stand – in socks – for the first time in the spot where King Charles III will be crowned.Guided “barefoot” tours in celebration of the 6 May coronation will include access to the Cosmati pavement, one of Britain’s greatest medieval art treasures, which is usually roped off to the public.It has been the site of the crowning of kings and queens for more than 700 years and was even hidden under carpet for 150 years from the 1870s until it was conserved in 2010.