The online contest has been dogged by technical problems and allegations of vote-rigging. The BBC reset all ratings to zero and said it would judge the 850 entrants individually, causing uproar among schools that thought they had made it to the shortlist of 20.

Caroline Stamp-Dod, a teacher at Millfield primary, Cambridgeshire, said the decision was probably the fairest option, but added: “I know children who were in the top 20 and cancelled holidays as they thought they were in with a chance. I feel desperately sad for them.’ The BBC admitted the contest had been “compromised by technical difficulties and evidence of block voting” and assured entrants that mistakes would not be repeated. The winner is Brampton primary, east London. Photograph: Tony Hardacre.