EU referendum: Peers' refusal to back down over voting age could scupper David Cameron's plan for summer poll

The constitutional face-off over giving 16-year-olds the vote threatens to leave the Bill in limbo

Members of Generation Yes - a youth and students campaigning for a Yes vote in Scotland's independence referendum last year. Labour and Liberal Democrat peers want the voting age lowered to 16 in time for the EU referendum (Getty)

Labour and Liberal Democrat peers are refusing to drop their plans to give 16- and 17-year-olds the vote, despite warnings it could scupper the prospect of David Cameron holding an EU referendum in the summer.

The Government is expected to set up a fresh showdown with the House of Lords this week by throwing out an upper house amendment to the EU Referendum Bill which would lower the voting age to 16.

But peers have vowed to defy the Government and reinstate the controversial amendment when it returns to the upper house.

The constitutional face-off threatens to leave the Bill in limbo, delaying the point at which Mr Cameron could call a vote.

It comes after the Prime Minister was forced to admit that he will not be able to strike a deal on his EU reform plan at this month’s summit of European leaders. The European Council President, Donald Tusk, claimed this would “pave the way for a deal in February”, giving Mr Cameron just enough time to call a vote for the summer.

The Prime Minister has promised an in/out vote on Britain’s membership of the European Union by the end of 2017, but he is widely expected to move more quickly.

David Cameron with young voters before the Scottish referendum, in which 16-year-olds could vote (Getty)

If Mr Cameron strikes a deal in February and calls an election immediately, anti-EU campaigners believe the vote could take place as early as Thursday 14 July. This is because a date for the referendum would take six weeks to be signed off by Parliament, followed by at least 10 weeks of campaigning. However, the date could still be delayed by the House of Lords’ refusal to drop plans to extend the franchise.

Before the expected showdown, the Foreign Secretary, Philip Hammond, has cleared space in the Commons diary for a vote on Tuesday, in which MPs are expected to kick out the Lords’ amendment. It had been suggested that some Tory Eurosceptics are prepared to back the peers’ amendment in an attempt to delay the referendum even further.

In order to give under-18s the chance to take part, the Electoral Commission is understood to need at least six to nine months to register the new voters. This would force the Government to delay any poll until September. However, the Electoral Commission has previously suggested that the enrolment of 1.5 million teenagers on the electoral register could take up to a year – pushing back any vote until 2017.

Government sources insist they are confident they have the numbers to throw out the peers’ attempt to lower the voting age. In expectation that MPs will reject the Lords amendment, time has been set aside in the upper house the following week to debate the proposal. If the peers refuse to back down, the amendment will go back to MPs for fresh consideration in a process known as “ping pong” between the houses.

However, this gives MPs only a few days, before they break up for Christmas on 17 December, to agree a deal, raising the possibility that the Government will have to wait until the New Year to defeat the Lords.

A senior Labour source in the House of Lords told The Independent on Sunday that there was a clear majority of peers determined to give 16- and 17-year-olds the vote.

Labour’s leader in the Lords, Baroness Smith, said: “The issue at stake ... is about energising young people to play their part in both the referendum itself and the broader debate on Britain’s future in the world .... The Government should not underestimate how important all of this is to Labour peers and others across the House, including some on the Conservative benches.

“I urge the Prime Minister to reconsider his opposition and to focus instead on making the case for our continued membership of the EU.”

Lady Smith defended the right of the Lords to hold up the EU referendum. “Our constitutional role involves scrutinising and improving legislation, and asking ministers to think again,” she said. “In this instance, widening the franchise and engaging more of the UK public will clearly add rather than take away from what the Government has proposed.”

The amendment to give those aged 16 and 17 the vote was tabled by Labour’s Baroness Morgan, with support from the Lib Dems and Tory peer Baron Tugendhat. It was passed last month with a majority of 82, with support from peers across the house.

The Government will be hopeful that the 82 majority could be chipped away, but Labour remains confident it has the numbers to see them off.

However, a senior Conservative peer said last night: “Labour and Lib Dems should not block or stall legislation that was clearly stated in our manifesto and which the British people gave us a mandate to pursue.

“The EU Referendum has already been backed by a majority of 45 in the Commons and will be so, clearly, again.

“Attempts by the Labour and Lib Dem front benches in the Lords to implement their rejected manifestos, ignoring the voice of the public, would be an abuse of the role of the House of Lords – as they and the whole House are well aware.”