Bercow's sin was to agree to work for Gordon Brown's Labour Government, with the blessing of the Conservatives, in 2007.
His son has autism, and it is a suject Bercow MP had long supported and campaigned about. When a review of Government Policy on autism was needed, Alan Duncan at the Department of Health asked Bercow to do it, having first sought permission from the Conservative leadership.
To a hardcore handful of Tory nutjobs, that made Bercow a traitor and they have never accepted his appointment.
In 2009 there were 10 candidates, and Bercow beat Lord Young in the final ballot to win 55% to 45%.
Bercow has been re-elected twice since. The same Tory nutjobs tried to unseat him on the last day of the last parluament but failed miserably.