In Ireland and the UK previous convictions needn't be disclosed in a case. In short so long as you enter no evidence as to your (good) character, then the Prosecution can't bring up any (bad) character you have
Here's a recent case as an example where a man was accused of burning down his house and killing his children. The highly relevant fact that he had attempted to murder a previous partner was left out.
Mick and Mairead Philpott convicted of manslaughter over Derby house fire | UK news | guardian.co.uk
Derby fire: Mick Philpott, guilty of killing his children, tried to murder previous girlfriend - Telegraph
I'm of the view that all previous convictions should be automatically disclosed - you ?