The Telegraph can disclose that fellow judges will include Liam Charles, a 24-year-old Great British Bake Off star, Jane Dunn, a food writer and blogger, and Regula Ysewijn, a food photographer and historian who has written six books including Pride and Pudding.
They will join Roger Pizey, the executive head of pastry at Fortnum & Mason, in a panel designed to appeal to all generations.
Mr Adlard, 30, who has no formal culinary training, shot to fame by “going topless” for a series of YouTube baking tutorials for an audience primarily consisting of 18-34 year olds. He runs online cookery school Bake It Better.
Despite the special events over the June Bank Holiday weekend, not everyone will be celebrating the Queen, who will then be 96. Republic, an anti-monarchy campaign group, will use the jubilee to publicise its “Not Another 70” project to end the reign of the Royal family.
Graham Smith, chief executive of Republic, called the monarchy a “shabby institution” which is “set against our nation’s deeply held democratic principles”.
