MPs back Scottish young voters plan
MPs have voted in favour of devolving powers which would allow Holyrood to set the franchise in Scottish Parliament and local government elections.
The move is expected to result in 16 and 17-year-olds being allowed to vote.
The measure was part of the package agreed by the Smith Commission.
It has been brought forward ahead of the other proposals so it can be implemented in time for next year's Holyrood election.
Scottish Secretary Alistair Carmichael told the Commons the move towards extending the franchise to 16 and 17-year-olds across the UK was "irresistible".
Mr Carmichael said it was "unthinkable" that 16 and 17-year-olds would not be able to vote in the 2020 general election.
Shadow Scottish secretary Margaret Curran warned against the emergence of a "two-tier voting" system, as opposition parties pressed for 16 and 17-year-olds to be given the vote in UK general elections.
The SNP's Westminster leader Angus Robertson also said it was "shameful" that the vote was not being extended to the age group for UK Parliament elections.
He said it was evidence of Conservatives in England ignoring the democratic will of the Scottish people, as 58 out of 59 Scottish MPs belong to parties who favour lowering the voting age.
Concluding the debate on the new regulations, Mr Carmichael said it was clear "all sorts of practical reasons" would stop 16 and 17-year-olds voting in May's general election.
Mr Carmichael, who told MPs he was speaking personally, added: "I think it is unthinkable that by the time we come to an election in 2020 that we will not see that election on a franchise that includes 16 and 17-year-olds.
"I think the move in that direction is now irresistible but, of course, that will be for the House to decide on another day."
Speaking earlier as he introduced the secondary legislation, Mr Carmichael commended the involvement of young people in last year's Scottish independence referendum, which he said was "truly historic and inspirational to witness."
For Labour, Ms Curran said: "If our young people in Scotland have what it takes to decide the future of their country in a referendum and soon the shape of the Scottish government, they have what it takes too to decide the shape of the UK government."
"That is why Labour would extend the franchise in all UK elections so that 16 and 17-year-olds can vote too in UK general elections."
Mr Robertson said: "I think all of us having gone through the independence referendum experience would want to make sure that that is not a one-off.
"And the fact that we can do it for Scottish Parliament elections is great, the fact that it will happen for local government elections is fantastic.
"The fact that it won't happen for Westminster elections is frankly shameful."
The transfer of powers to lower the voting age is being carried out through what is known as a section 30 order.
Prime Minister David Cameron has said he is personally opposed to votes for those under the age of 18.
But he agreed during a meeting with First Minister Nicola Sturgeon in December that it was appropriate for Holyrood to decide.