Sixteen and 17-year-olds would be able to vote at the next general election, under government plans to lower the voting age.
The pledge is part of a raft of measures being introduced through a new Elections Bill.
Other changes include expanding forms of voter ID to include UK-issued bank cards, moving towards automatic voter registration and tightening rules on political donations to protect against foreign interference.
The minimum voting age is already 16 for local council elections in Scotland and Wales, and elections to the Senedd and Scottish Parliament. However for other elections, including to the UK Parliament, local elections in England and all elections in Northern Ireland, it is 18.
Deputy Prime Minister Angela Rayner told the BBC: "I was a mum at 16, you can go to work, you can pay your taxes and I think that people should have a vote at 16."
However, Conservative shadow minister Paul Holmes said the government's position was "hopelessly confused".
"Why does this government think a 16-year-old can vote but not be allowed to buy a lottery ticket, an alcoholic drink, marry, or go to war, or even stand in the elections they're voting in?" he asked in the Commons.
Critics of the idea argue it could benefit Labour as young people are more likely to vote for left-wing parties. However, polls suggest Labour's youth vote is at risk of being chipped away at – by the Greens, Liberal Democrats and Reform UK.