So Mr. Gore reversed field again and swung back to his aggressive ways in the third debate.

FORBES: Debate III: Overcompensation?

But it was not regarded as a great success by the players - and the experiment was dropped after one season after no decisions made by on-field umpires were reversed.

BBC: Referrals change for England tour

The off-field umpire must find 'compelling evidence' from the technology available to suggest to the on-field umpire that his decision should be reversed.

BBC: Jonathan Agnew column