Monty Don, Rachel de Thame and Joe Swift preview the 25th Royal Horticultural Society's Hampton Court Palace Flower Show, which this year is celebrating its silver anniversary. In the first of four programmes, Monty Don and Joe Swift look back to the show's beginnings back in 1990 and talk to the exhibitors who have been at the show since the start. Rachel de Thame talks to the Historic Rose Group, and chief curator of the Royal Palaces Lucy Worsley explores Hampton's famous maze.