2. Danny Cipriani & Mike Catt
Teammates for England’s 2007 Rugby World Cup training squad, eight years later the two clashed ahead of the 2015 showpiece when Catt had joined Stuart Lancaster’s backroom staff. Catt over-reacted to a perceived lack of effort in a training drill and allegedly told the 27-year-old twice: ‘I will end your England career’. The two haven’t been on speaking terms since.