A new study has revealed that up to 9.4 million people are not registered properly to vote, leading to calls to reform the system.
The research, published by the Electoral Commission, found that 9.4 million people are not registered at their correct address, while 5.6 million people are registered incorrectly.
Only 71% of people aged between 18 and 34 are correctly registered to vote, compared to 94% of people aged 65 and over, the research found.
Chair of the commission, Sir John Holmes, said: 'Giving electoral administrators access to reliable and trusted public data would help them more easily identify people who have moved and may be eligible to register to vote.
'Being able to change your electoral registration details while, for example, updating your driving licence could be another way of making it easier for people to ensure they are registered.'
A spokeswoman for the Association of Electoral Administrators (AEA) added: 'At an AEA meeting of 500 electoral administrators earlier this month, 65% said they were struggling to access data sources.
'Better access to local data such as council tax records, cooperation from universities to help register students and information exchanges with national bodies would help to boost the numbers of potential electors being invited to register to vote.'