New figures show that 740 people were denied a vote in the latest local elections due to the government's voter ID trials.
In the second year of trials, voters in 10 areas in the May local elections were required to show ID ranging from poll cards with electronic scanning to photographic documents including driving licences.
A new report into the trial found 740 were turned away at polling stations for not having ID and did not return to cast their vote.
Dr Jess Garland, director of policy and Research at the Electoral Reform Society, said: 'These official figures pose a stark warning about the government’s undemocratic push for mandatory voter ID. It is clear that, once again, the number of people denied their rightful vote far outstrips the levels of impersonation at the ballot box.
'Mandatory voter ID poses an unprecedented risk to democratic access and equality. Millions lack the required forms of identification and these plans, if rolled out nationwide, could see tens of thousands of legitimate voters lose their voice.'
However, the Government said the latest round of election ID trials were a success with fewer than 0.5% of would-be voters who were turned away failing to return with the correct paperwork.
The highest proportion was in Derby where 0.6% of voters who were turned away – 256 people – did not return.
It also aid a survey of voters showed they were more confident that elections were secure from fraud if they were required to show identification documents before being allowed to vote.
Minister for the constitution Kevin Foster said: 'Stealing someone’s vote is stealing their voice and any instance of this is an unacceptable crime.
'The very perception our current electoral system could allow voter fraud undermines its integrity.
'This Government has always maintained that voter ID is a reasonable and proportionate measure to prevent this and today’s data provides further, welcomed analysis to support this.'
Cat Smith, Labour’s shadow minister for voter engagement, argued: 'It is now clear that the Government’s fixation with Voter ID is a blatant attempt by the Tories to rig the result of future elections by voter suppression.'
In May, a coalition of charities, civil society figures and campaign groups warned that millions of people would be denied a vote if the scheme went ahead nationwide.