A last-minute surge in people registering to vote is expected ahead of the deadline on Tuesday night.
Applications can be submitted until 11.59pm on November 26.
Nearly three million people have applied to register to vote in the past month, according to Government figures.
More than a third of those applications (35%) have come from people under the age of 25.
A further 30% have come from people aged 25 to 34.
By contrast just 4% have been submitted by people aged 65 and over.
Of the 2.98 million applications submitted between October 24 and November 24, the biggest spike was on November 22 when nearly 308,000 were recorded.
An increase in applications is not direct evidence of an increase in the number of people able to vote.
At previous elections there have been applications from people below the legal age to vote or who are already on the electoral register.
Nonetheless, the volume of applications suggests a growing interest in participating in the election.
To be able to vote in the General Election on December 12, a person must be registered to vote, aged 18 or over on polling day, and also be either a UK or Irish citizen or a qualifying Commonwealth citizen resident in the UK.
Applications to register to vote can be made online at gov.uk/register-to-vote.