Election day: Investigation into turned-away Barnet voters
Barnet Council has apologised after voters were turned away from polling stations.
The authority has promised an investigation into how some people were unable to vote because their names were missing from the poll list.
It confirmed all 155 polling stations had been affected but said staff had accurate registers by 10:30 BST.
Voters whose names were missing had been allowed to apply for an emergency proxy vote.
London has been voting for a new mayor and the London Assembly, as voters went to the polls in a range of local and national elections across the UK.
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In a sign of how extensive the problems were, staff at one station said that of the first 30 voters to show up, only three were on the register. The rest were told to come back later.
The Barnet and Camden constituency returning officer, Andrew Travers, said: "We did everything we could to resolve the issue as quickly as possible and updated lists were sent to every polling station by 10:30, at which point all residents were able to vote as normal.
"Taking part in the democratic process is a fundamental right for our residents and the main focus this morning was to resolve the situation as soon as possible. We will fully investigate the cause of the problems that have arisen. I would like to apologise to everyone who experienced problems with voting in Barnet today."
Staff were told a "printing error" was to blame. The council said it was unable to confirm how many of the 236,196 people registered to vote had been affected by its mistake.
Black cab driver Adam Barnett said the mix-up meant he would have to go back to the polling station for the third time in one day to cast his vote.
He said he was first turned away at 07:00 from the polling station in Bells Hill.
"I was one of a number of people who had turned up first thing and couldn't vote. They still hadn't got the updated list when I went back a second time after 10. It's just a farce," he said.
Voter David Fraser was among those turned away. "I'm now not going to be able to vote," he said. "I don't have time to go back."
Another voter, in Golders Green, told the BBC he was turned away from a station in Oakfields Road, Temple Fortune.
He said: "I got up early so that I could get to the polling station at 08:00 before work.
"But when I got there, they said my name is not on the list and that there was a problem.
"I am so disappointed. I like voting as it is the right thing to do and it is a democratic right."
Others took to Twitter to complain.
"Frustration turning to real anger," Neil Maiden tweeted. "After 35 minutes, only five people have been able to vote. What are the wider implications?"
The Electoral Commission, an independent body that sets standards for running elections, said the only provision for re-running an election in Barnet was if the result was challenged by a constituent after voting closed.
It said in that instance the legal challenge had to be raised with the Royal Courts of Justice within 21 days.
A spokesman for the commission said: "Barnet has apologised for its error and the matter was resolved quite quickly."