A signed copy of ‘The World’s Worst Children 2’ by David Walliams A signed hardback copy of 'The World's Worst Children 2' by Britain's Got Talent judge David Walliams is the ideal gift for you son, daughter, niece or nephew with a wicked sense of humour. What the winning bid will receive: A signed hardback copy of 'The World's Worst Children 2' by David Walliams.