About 340 people in five areas of England were turned away from voting in council elections because of a pilot scheme requiring proof of identity.
At least 688 were initially stopped but later returned to the polling station with the correct documents.
The Electoral Reform Society said requiring ID risked denying people their “democratic right”.
The government said an “overwhelming majority” of voters had the right documents.
via Voter ID: 340 did not vote after failing to show documents – BBC News