The Government must explain why a new law to make voter ID mandatory is both necessary and proportionate, MPs and peers have said today.

A report by the Joint Committee on Human Rights said the Government must do more to explain why the move was needed and how it intended to mitigate the potential barriers to voting.

The report called for more detail on how the proposed voter ID card will operate in practice and urged the Government to consider introducing automatic voter registration to ensure those who are entitled to vote can do so.

Chair of the committee, Harriet Harman, said: 'The Government has a duty to ensure everyone can vote and no one is prevented from voting by discrimination and also that elections are free from fraud.

'However, current proposals, which would prohibit voting without voter ID, may deny the right to vote from large numbers of electors and could have a discriminatory impact.

'The Government must explain how these measures are both necessary and proportionate given the low numbers of recorded instances of fraud at polling stations.

'The Government must prove that the need for people to get a voter ID card does not act as a deterrent to voting.

'In particular, they must demonstrate an understanding - so far lacking - of the impact of these measures on marginalised groups and show how they plan to ensure access to the ballot box for all.'

Under the proposal, councils will be required to issue free voter cards for people without the correct identification.

Director of policy and research at the Electoral Reform Society campaign group, Jess Garland, said: ‘The Government has failed to make a credible case that these measures are necessary just as they have failed to take any serious steps to reduce the negative impacts of these dangerous proposals.

‘Make no mistake, voter ID will see legitimate voters turned away from the ballot box. It's time for the Government to stop and rethink.'