The digital campaign has been created by Dare. It converts tweets by users who register on a dedicated website. The tweets must contain the hashtag #voice and the hashtag of the nominee.
They can also view other peoples' supportive tweets from the site.
Barclaycard began sponsoring the Mercury Music Prize in 2009 as part of a four-year sponsorship deal. This year artists Plan B and Richard Hawley are both tipped to win the prize. Other artists whose albums are among the 12 nominated include Django Django, Jessie Ware and Michael Kiwanuka. The winner will be unveiled on Thursday 1 November.Follow @shearmans