Civil liberties groups, electoral reformers and senior MPs on both sides of the Commons have condemned government plans to introduce a requirement for voters to prove their identity before casting their ballot.
Downing Street said it was a “reasonable approach” and 99.6% of people in pilots requiring people to show photographic ID had managed to vote without difficulty.
The government has defended the move as an attempt to combat electoral fraud, but Tory former cabinet minister David Davis said it was an “illiberal solution for a non-existent problem”.
Legislation on the issue will be included in the Queen’s Speech on Tuesday.
The prime minister’s official spokesman said: “Showing ID to vote is a reasonable approach to combat the inexcusable potential for voter fraud in our current system and to strengthen the integrity of our elections.
“Showing ID is something people do when they pick up a parcel at the post office or a library book.
“The 2019 voter ID pilots showed that in elections where photo ID was required, 99.6% of electors were able to cast their votes without a problem.”
The Tory 2019 manifesto committed to introducing the requirement to produce identification in order to vote at a polling station.
But Davis told The Independent: “It’s yet another unnecessary ID card approach from the government… There’s no evidence that I’m aware of that there is a problem with voter fraud at polling station.”
Campaigners warned that people without ID would be disenfranchised as a result of the move, especially those in marginalised groups.
Shadow democracy minister Cat Smith said 3.5 million voters did not have photographic ID.
“The chances are we all know someone without photo ID, maybe it’s your Nan, your son, your mate from the football? Don’t have a driving licence, don’t travel abroad?”
She added: “This policy will put up obstacles for poorer voters. It wants in the bin.”
Jess Garland, director of policy and research at the Electoral Reform Society, said: “David Davis is right: this policy is a solution in search of a problem.
“Voting is safe and secure in the UK, meaning this policy is just an unnecessary barrier to democratic participation. Ministers need to listen to these concerns and drop these costly plans.
“Millions of people lack photo ID in this country. These proposals will make it harder to vote for huge numbers of voters, locking ordinary people out of our democracy and unfairly discriminating against those who lack ID.”
Sam Grant, head of policy and campaigns at Liberty, said: “Millions of people in the UK don’t have photo ID, and the vast majority of them come from communities that are already marginalised and under-represented by our political system.
“Meanwhile the government’s own findings show our current voting system is safe and secure. Instead of creating more barriers to voting, Ministers should focus on making it easier for everyone to vote, and ensuring we can all have an equal say in our democratic process.
“As there is no justification for this threat to the right to vote, it feels like an opportunistic attack on the rights of some of the most marginalised people in society, a classic example of ruling through division and distrust.”
Under the government’s plans, rules will be tightened on absent voting and voter intimidation as the government aims to “stamp out” fraud.
Measures set to be announced next week will include a ban on postal vote harvesting by limiting the number of votes a person can hand in at a polling station on behalf of others.
Voter intimidation is also expected to be listed as a form of undue influence in law, in order to prevent people from being coerced into giving up control over their vote.
Constitution minister Chloe Smith, said: “Stealing someone’s vote is stealing their voice. Fraud, and the intent to intimidate or coerce a voter, are crimes.
“So this government is stamping out the space for such damage to take place in our elections.”