Britain’s Electoral Commission has opened an investigation after thousands of people were unable to vote in the general election because of an unusually high turnout.
There were extraordinary scenes at a polling station in the north London borough of Islington as voters clashed with officials.
There were late rushes on the polls in several parts of the country.
Some voters say they were turned away after waiting for hours which sparked confrontations.
All the major parties have expressed concern about the reports.
One of the worst affected areas was the electoral district of Sheffield Hallam in northern England, the area represented by Nick Clegg, leader of the Liberal Democrats.