'This is our chance to hurt Cameron'

Peter Mandelson enters the AV debate and tells Labour voters, use your noddle to defeat Tories.

David Cameron is today accused of cynically turning the referendum campaign on the voting system into a bitter row between the Conservatives and Liberal Democrats to head off a Yes vote. In his first intervention in the AV referendum, Lord Mandelson, the former Labour cabinet minister, claimed that the Prime Minister had adopted a high-profile role in the No campaign in order to divert media and public attention away from a debate about the alternative vote (AV).

In an interview with The Independent, Lord Mandelson warned Labour figures who are backing the No camp that their actions could condemn the party to years in the electoral wilderness. He appealed to Labour supporters to vote Yes in next week's referendum to damage the Tories and undermine Mr Cameron's position.

Lord Mandelson's intervention reflects fears in the Yes lobby that the Prime Minister's strategy will deliver a high turnout among Tory supporters for a No vote. The Yes camp will target Labour sympathisers in the run-up to the referendum, believing that offers the best hope of turning round the opinion polls, which suggest that the public will reject reform. Most surveys show a narrow margin against AV among Labour supporters.

There is even speculation at Westminster that Mr Cameron, if strengthened by a No verdict, might call a general election this autumn rather than maintain the Coalition with the Liberal Democrats. Despite their increasingly bitter battle over AV, that looks unlikely, with both parties insisting that the Coalition will return to normal business on 6 May. Privately, Labour would not welcome an early election.

Lord Mandelson, Labour's former election strategist, claimed that Mr Cameron had "pressed the panic button" because he feared a Yes vote in the referendum. "Labour shouldn't ignore this chance to defeat the Tories on 5 May," he said. "Labour supporters need to use their noddle and ask themselves why Cameron is fighting so hard for a No vote. He's fighting for his party's interests but also to protect his own leadership.

"Labour has a chance to inflict damage on both. Cameron has been forced to intervene, to turn it into an intra-Coalition partisan scrap in order to mobilise Tory support and Tory-supporting newspapers."

Lord Mandelson, a long-standing supporter of AV, said: "Labour people need to question why Cameron is suddenly so desperate for a No vote. Because a Yes vote would send the Tories into convulsions and greatly weaken him. Right-wing Tories have already been gravely warning it would make Cameron a 'lost leader'. That is something Labour supporters should bear in mind as they consider their vote."

A week after the former Labour minister John Reid shared a No platform with the Prime Minister, Lord Mandelson said: "Too many in Labour have shown the wrong priority in this referendum: a short-term desire to kick Nick Clegg, rather than see the long-term benefit of defeating Cameron and obtaining the beneficial consequences of AV."

He warned Labour backers of the first-past-the-post system: "If AV is defeated, the Tories will be greatly helped in creating the conditions for electoral dominance, with Labour governments at risk again of becoming the exception rather than the norm."

Lord Mandelson's plea is bound to be dismissed by the Tories as a sign of the Yes camp's desperation and an appeal for Labour supporters to show their tribal instincts rather than vote on the merits of the two electoral systems.

There is little sign of the Labour politicians backing the No camp pulling their punches. Margaret Beckett, the former foreign secretary, will campaign alongside the Tory Culture Secretary, Jeremy Hunt, today. She said last night: "With just days to go, it is more important than ever that we put aside party differences for the good of the country and that everyone comes out to vote against the unfair and expensive AV system on 5 May." Mrs Beckett insisted that she wanted a proper debate on the merits of AV and first past the post. "I strongly urge people to look at the two voting systems in this contest and they'll see that our current system is simple, fair and decisive; whereas AV is an expensive and complicated political fudge," she said.

Yesterday a senior Tory MP told Mr Clegg and the Energy Secretary, Chris Huhne, to stop "whingeing" about the No camp's tactics. Mark Pritchard, secretary of the1922 Committee, said: "With each of them presiding over major government departments, they've never had it so good. Their personal and political sacrifices are infinitesimal compared to those made by the hundreds of public-sector workers losing their jobs each week and many Conservative colleagues who gave up ministerial office for the sake of the Coalition."