‘Since 1969 no convicted prisoner in the UK has been allowed to vote. This prohibition was imposed, without debate, by the Representation of the People Act 1969. For two years before that there was no statutory bar to prisoners voting by post, albeit that there were, in many cases, administrative restrictions that prevented them from doing so.’
Halsbury’s Law Exchange, 30th June 2014
Source: www.halsburyslawexchange.co.uk
