Government challenged to reduce voting age after it drops opposition to 16-year-olds taking part in Scottish independence referendum

The Government was tonight challenged to lower the voting age across the United Kingdom after it dropped its opposition to 16 year olds taking part in the planned referendum on Scottish independence.

Supporters of the move believe the concession to Scottish voters will revive the controversy over when teenagers should be allowed to participate in general elections.

Senior Conservatives are hostile to the plan, although Tory sources acknowledged that the decision would put the issue back on the wider constitutional agenda for the UK.

Tonight critics accused the Conservatives of acting in self-interest by defending the status quo as young adults are less likely than any other age group to support the party.

The Tories picked up just 30 per cent support among 18 to 24 year olds at the last election, compared with 37 per cent across the electorate as a whole. It was the only group where the Conservatives lagged behind Labour.

The Liberal Democrats are in favour of lowering the franchise and Labour is expected to support the step its next manifesto.

The move would boost the British electorate by about 1.5 million and proponents believe it would help to engage younger people in the political process.

Mr Cameron will meet the Scottish first minister, Alex Salmond, next week to agree the terms of the referendum which will take place in the autumn of 2014.

Although agreement has not been reached on some details, the broad outline of the vote has emerged. Scottish voters will be asked a simple yes/no question of whether they want to remain in the UK, which is a key demand of the UK Government.

In return, the electorate for the referendum will be extended to 16 and 17-year-olds, which the Scottish Nationalists believe will increase the chances of the independence vote being carried.

Tonight supporters of electoral reform urged Mr Cameron to seize the moment to widen the franchise across the United Kingdom.

The Labour MP Natascha Engel said: “I’m really excited about what’s happening in Scotland. People should have the right to have a say over the issues that affect them – it’s a real denial of fundamental human rights for people who are 16.”

Willie Sullivan, the Scottish director of the Electoral Reform Society, said: “If 16 year olds are to be granted a vote on the future of the Union, it would be ridiculous not to give them a say on the trifling matter of their next local MP.”

Michael Dugher, the shadow Cabinet Office minister, said: “It might just do our democracy some good by making politicians listen to our young people.

“I can see why Tories might be against – you’re unlikely to vote for Cameron if he’s taken away your educational maintenance allowance, hiked up your tuition fees or if you face joining the one million young people on the dole.”

The Communities minister Don Foster, who is a Liberal Democrat, said: “The fact there are people who are arguing for votes at 16 for a political purpose strengthens the case for votes at 16 more widely.”

Grant Costello, the chair of the Scottish Youth Parliament, described the referendum as a “seminal moment for Scottish democracy”. He added: “Allowing 16-year-olds to vote in this referendum will pave the way for the franchise to be extended in all future elections. After all, if we trust young people to vote on Scotland’s constitutional future, then we must surely see the case for allowing them to vote in all elections.”

But a Conservative minister said: “We will oppose it for Westminster, we will say ‘no’ to that idea.” A Downing Street source added that there were “no plans” to look afresh at the voting age.

At the Tory conference today, Mr Cameron appealed to his party to campaign against Scottish independence with “everything we've got”. He said: “There are many things I want this coalition to achieve, but what could matter more than saving our United Kingdom?”

Mr Salmond said: “Great progress has been made and I’m certainly hoping and optimistic that a deal can be done next week. But a deal ain’t done until it is finalised. There are a number of issues that are still to be resolved.”

It was initially believed that 16 and 17 year olds would be more enthusiastic about independence than older Scots, although polls suggest the youngest and oldest votes are most opposed to a breakaway than other groups.

A survey this week showed opposition to independence hardening in Scotland. It found that 53 per cent said they would vote against, compared with 28 per cent in favour of breaking up the UK.