General election 2017: Theresa May rules out votes at 16
Theresa May has ruled out lowering the voting age at UK elections if the Conservatives win power on 8 June.
Labour, the Lib Dems, the SNP and the Greens all back votes at 16 - only UKIP and the Tories are against it.
Sixteen-and 17-year-olds were allowed to take part in 2014's Scottish independence referendum.
But Mrs May will tell BBC Radio 4's Westminster Hour she believed it was "right" to keep the current minimum age of 18 at UK-wide elections.
"This is one of those questions where you have to draw a line," she will say in an interview to be broadcast at 2200 GMT.
"You have to pick a point at which you think it is right for the voting age to be. I continue to think it is right for it to be 18."
In an interview with presenter Carolyn Quinn, she argued there are other ways for young people to participate, saying: "The implication from your question is that the only way to get engaged in politics is by casting a vote.
"I think it is important young people watch politics, pay attention to politics, get to think about their own views and where possible start to get involved."
Asked what Conservatives were offering to appeal to young people, she called attention to forthcoming talks on Brexit.
"We have to get those negotiations right and we have to get them right for those young people's futures," she said.
She was also challenged on changes to the housing benefit element of Universal Credit which exclude 18- to 21-year-olds.
She told the Westminster Hour: "I don't think any of us wants to see any one sleeping rough on our streets.
"We are putting £500m over these five years into homelessness, into preventing homelessness."
What are the other parties saying?
Green Party co-leader Caroline Lucas told the BBC: "We should be trusting young people to have a real say about the future direction of their country, not shutting them out."
SNP deputy leader Angus Robertson highlighted that as well as voting in the 2014 referendum, Scottish 16- and 17-year-olds can vote in local and Holyrood elections.
"It is ridiculous that thousands of young people who voted in the Scottish local elections just weeks ago are now being denied a say on their future in this Westminster election," he said.
Lib Dem spokesman Tom Brake accused Theresa May of "robbing young people of future opportunities through her damaging hard Brexit agenda", adding: "It's no surprise she is now refusing to give 16- and 17-year-olds the vote."