Willis claimed, in his guise as a broadcast pundit, that umpire Aleem Dar was "on England's case" and knew that an unnamed player was scratching the ball. His comments came after Dar and fellow on-field umpire Billy Bowden initiated a change of ball during England's group stage defeat by Sri Lanka at The Oval.
England coach Ashley Giles issued a firm denial of anything untoward, and the International Cricket Council made it clear there was no reason from anything in the umpires' report to conduct any further investigation. Bopara told the London Evening Standard: "It was annoying, sad and depressing - especially in the middle of a global competition."
He added: "We were doing well in that tournament, and I felt it was unacceptable to make that sort of noise.
"When England are doing well, why does something negative have to come from it? Why not just get on the wave with England and enjoy it?"
Bopara, often tasked with the job of looking after the ball for both his county and his country, went on to say: "We've learned over the last 12-18 months that we need to look after the white ball as well as we do the red ball.
"We discussed as a team how we were going to shine it.
"You have to look after them to make them 'talk'.
"You want that seam to be standing up as long as possible; you want one side to be very smooth, which helps with lateral movement.
"If you can make the red ball swing, you should be able to do the same with the white one."