Rivals share platforms as AV battle intensifies

In one of the more curious pairings of the modern political era, David Cameron will today share a platform with the Labour former cabinet heavyweight John Reid as the battle over electoral reform escalates and cuts across party lines.

At the same time, the Liberal Democrat cabinet minister Vince Cable will be sitting alongside the Labour leader, Ed Miliband, to make the case for changing the voting system.

With 17 days to go to the referendum, politicians are to intensify hostilities in a contest that is too close to call.

Tensions within the Coalition – inflamed last week by Mr Cameron's warning that high immigration had damaged some communities – have been exacerbated by the referendum campaign. The differences were underscored yesterday by rival television interviews by the Prime Minister and his deputy. Mr Cameron claimed that first-past-the-post was straightforward and popular around the world, while Nick Clegg countered that the alternative vote was fairer and more democratic.

The Prime Minister also echoed George Osborne's allegation that the commercial arm of the Electoral Reform Society, the biggest financial backer of the Yes campaign, stood to profit from a switch to AV. Electoral Reform Services Ltd denies any conflict of interest. Mr Cameron told Sky News: "That's a fact and I think there is nothing wrong about bringing that fact out." The repeated assertion has infuriated the Yes camp. The former Liberal Democrat leader Lord Ashdown said Mr Osborne's strategy "stinks of the same odour which has surrounded our politics recently".

Mr Cameron will be joined by the former Labour cabinet minister Lord Reid as he steps up his attack on AV. He will claim that the vote on 5 May is crucial to "the future of our democracy". He will say: "The biggest danger right now is that Britain sleepwalks into this second-rate system, waking up on May 6 with a voting system that damages our democracy permanently. We must not let that happen."

Lord Reid will argue that first-past-the-post has been the "foundation of our democracy for generations" and had been "copied by democracies the world over". He will say: "There are some issues so important that they transcend party politics, issues on which people expect politicians to put aside their party differences for the sake of the people and the public interest."

Meanwhile Mr Cable will today defy his Tory critics by taking to the stage with Mr Miliband to make the case for electoral reform. The Business Secretary has ruffled feathers within the Coalition with his attack on Mr Cameron's "very unwise" speech last week on immigration. Today he will find common cause with the Labour leader to argue that a system under which an MP requires 50 per cent support to be elected will strengthen links with voters.

Mr Clegg told BBC 1 yesterday: "After the expenses scandals, people want some change. They want the system cleaned up. They want a system which I think would be delivered by AV which is fairer, which makes MPs work harder for your vote, which makes every vote count. It's actually a relatively modest change to the current system."