On 1 March 2014, at a special conference the party reformed internal Labour election procedures, including replacing the electoral college system for selecting new leaders with a "one member, one vote" system following the recommendation of a review by former general-secretary Ray Collins. Mass membership would be encouraged by allowing "registered supporters" to join at a low cost, as well as full membership. Members from the trade unions would also have to explicitly "opt in" rather than "opt out" of paying a political levy to Labour.
Who was allowed to join at a high cost?
{'text': 'registered supporters', 'answer_start': 340}