Calls are growing for the voter registration deadline to be extended after the website for people to register to vote online crashed just hours before the deadline.

People trying to register to vote reported errors and timeouts as the midnight deadline for eligibility to vote in the 23 June referendum approached last night.

At 10.15pm on Tuesday there were over 50,000 users accessing the voter registration website at any one time and attempting to sign up before the deadline.

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Howver by 10.45pm the website stopped letting people through.

Tests by The Independent showed the main webpage accessible, but the button to proceed with the process inoperable.

A number of other web users also reported problems with the system.

At 11.10pm the website was providing intermittent service, with some requests being allowed and others blocked. Some users that kept trying were able to succesfully register.

Jeremy Corbyn said the deadline should be extended (Reuters)

The problems prompted calls for the deadline to be extended due to the technical issues.

Labour leader Jeremy Corbyn led the calls, tweeting: "I'm told the site has crashed so people can't register to vote for #EUreferendum. If so, deadline has to be extended."

Labour MP Yvette Cooper said: "If this is right, deadline must be extended. People can't be denied right to vote because computer says no."

“This is a shambles the government has presided over and people must be given an extra day to exercise their democratic right,” Lib Dem Leader Tim Farron said.

“It is also a major blow to the ‘In’ campaign and our prospects of staying in Europe.

“With individual voter registration, and a big campaign to encourage young people to register, many of whom have been trying to do so last minute, this could have major consequences for the result,” he added. “Evidence shows younger people are overwhelmingly pro-European, and if they are disenfranchised it could cost us our place in Europe. Voters must be given an extra day while this mess is sorted out urgently.”

The technology problems mean that some people who want to vote in the European Union referendum may not be able to do so, unless a last-minute extension is granted or service resumes.

Hundreds of thousands of people have signed up on the voter registration website in the last few days before the deadline after a drive to get them to sign up.

Government statistics suggest most of the people signing up are relatively young - good news for the Remain campaign, which has been able to count on youth support in polls.

A disproportionate number of young people signups is to be expected, however, because older people are less likely to move house and are more likely to already be on the register.

The website gave users timeout errors

Earlier, the Vote Leave campaign was accused of using "underhand tactics" after it used a Google advert to place its own website above the official voter registration page.

That website appeared to instruct people to "register to vote now" but in fact simply harvested the details of people who used it. It did not register them to vote.

As of later this afternoon the website has been taken down. Vote Leave have not responded to requests for comment.