Schools, teachers and students had reasonably expected that those taking the June examinations would be treated the same as students who had sat earlier papers and handed in controlled assessments, argued Clive Sheldon QC, acting for the alliance.
The exam boards and Ofqual knew at the time of the publication of the January grades that this reasonable expectation might be disturbed but did nothing to let schools, teachers and students know that extreme changes might take place in the summer, he said.
Mr Sheldon told Lord Justice Elias and Mrs Justice Sharp at the High Court hearing that there could be no doubt that there was "grade manipulation" by the examination boards to meet Ofqual's "statistical fix" and this was an unlawful abuse of power.
More top news
Storm Imogen - when and where we will see the strongest winds? ITV Weather's Manali Lukha gives the breakdown.
Kate Middleton attended a special service to celebrate the landmark occasion in her first engagement as Honorary Air Commandant
The ISIS execution gang fronted by 'Jihadi John' had two British extremists who learned radical Islam together in London, ITV News reveals.