Millions of people not yet registered to vote are being urged to sign up ahead of the deadline later.
Tuesday is the last day for voters to register in time for the general election, with the deadline 23:59 BST on 18 June.
Just over 2.1 million people have registered since the election was called in May, government data shows.
Registering takes about five minutes online here with the election just over two weeks away on Thursday 4 July.
Government data shows last Thursday was the busiest day for people registering to vote this year – with 330,621 applications submitted. This included 75,605 people aged 18 to 24.
But the Electoral Commission says young people, private renters and those who have recently moved house are less likely to be correctly registered to vote.
Research by the body – which oversees elections in the UK – found nearly eight million people were not correctly registered in 2022.
Its report published last year revealed that nearly one third of 20 to 24-year-olds were not registered to vote in 2022.
That figure was even higher for 18 and 19-year-olds, with 40% of those not registered to vote.
By comparison, 96% of over-65s were registered, and 94% of those aged 55 to 64.
But the Electoral Commission’s report said the level has been “broadly stable across the UK” except in Northern Ireland which has seen a “significant increase” in registration levels since 2018, and in Wales which has also seen an increase although to a lesser extent.
“A general election is an important opportunity for people to express their views, and registering is the first step to the ballot box,” said Jackie Killeen from the Electoral Commission.
Anyone who wants to apply for a postal or proxy vote has more time to apply.
The deadline for postal applications is 17:00 on Wednesday 19 June, while for a proxy vote the cut-off is 17:00 on Tuesday 26 June. The deadline to apply for a postal or proxy vote in Northern Ireland has already passed.
Those voting at polling stations will also need to show photo ID – and the Electoral Commission is calling on people to check they have one of the 22 accepted forms of ID.