Wales abolished it in 2019
Welsh councils lost the power to apply for committal for council tax debt in April 2019. Enforcement continues through bailiffs, attachment of earnings and other means but not through imprisonment.
This applies to all Welsh council tax debts, historic and current.
Scotland uses different enforcement
Scotland does not have the English committal framework. Council tax enforcement in Scotland uses Sheriff Officers (the Scottish equivalent of enforcement agents), arrestment of earnings, and arrestment of bank accounts.
Imprisonment for council tax debt has never been part of Scottish enforcement.
England still has it
Only in England can non-payment of council tax lead to committal proceedings. Even in England it is rare and requires proof of wilful refusal or culpable neglect.