Historic Royal Palaces said the "Superbloom" display will transform the moat around the historic tourist attraction. Gardeners are set to sow more than 20 million seeds in the spring. From June to September the flowers will erupt, with visitors wandering on a weaving path into the centre of the blooms. Plants including cornflowers, sunflowers, gypsophila, poppies and pink cosmos have been chosen to attract bees and other pollinators. There will also be a specially commissioned sound installation and sculptures.

       Historic Royal Palaces said: "Superbloom will bring a spectacular natural beauty to the urban space and introduce a new biodiverse habitat for wildlife. It will celebrate the value of nature for our wellbeing."

       When the display ends in September, the new natural landscape will remain as a permanent Jubilee legacy. Preparation work for the spectacle has already begun.

       The 13th-century defensive ditch at the fortress has been used as a medieval orchard, a grazing ground for victorian livestock and as allotments during the Second World War.

       The moat featured a garden display for the 1977 Silver Jubilee and a breathtaking array of ceramic poppies in 2014. The Queen, who has sprained her back and remains on light duties, will reach 70 years on the throne in February. ??Display tickets go on sale at hrp.org.uk on December 6