A "thorough review" into incidents around the country where people were unable to vote by the time polls closed at 10pm has been pledged by the Electoral Commission.

Hundreds of would-be voters in areas including London, Sheffield, Manchester, Liverpool and Newcastle were prevented from casting their votes because of long queues.

The commission said it was a cause for "serious concern" that many people who wanted to vote were prevented from doing so, and said there should have been sufficient resources allocated to make sure everyone was able to vote.

Hundreds of people found themselves unable to vote at polling stations as they were still queuing when the ballot boxes closed.

Voters were turned away from polling stations in Sheffield Hallam, where Liberal Democrat leader Nick Clegg was standing. John Mothersole, returning officer for Sheffield, apologised to residents who were unable to vote.

Voters in Hackney, east London, were turned away from a polling station in Triangle Road, with some claiming they had been foced to wait for more than an hour and a half.

And police were called to a polling station in Manwood Road in Lewisham, south London, where around 300 people had yet to vote by 10pm.