Both Labour and the Conservatives will find it hard to win a "full mandate" from British voters at the general election due to the break down of two party politics, shadow education secretary Tristram Hunt has said.
Hunt said on Tuesday evening that Ed Miliband faced a "particular challenge" in 2015 because Labour was now the only UK-wide party.
With the election less than seven months away, Hunt said political leaders had to deal with the "spectre of mandate free politics" in Britain.
"Whoever wins at the next election might not have a full mandate to deliver a full programme," he said. "We are obviously fighting very hard for a mandate."
Hunt was speaking at an event in parliament organised by the New Labour pressure group Progress. "There is a particular challenge for the Labour Party, because we are the last party of the union. We are the last UK political party."
The shadow cabinet minister, a historian by trade, compared Miliband's predicament to that of King Charles. "Poor King Charles, he tried to hold Great Britain together while dealing with the Irish, the Scottish and the English and each one was pulling in different directions. For the Labour party we face the challenge of the SNP in Scotland and the challenge of Ukip in England."
"We are unique in facing these political challenges in different parts of the UK whilst remaining a strong unionist party," he said. Hunt said Britain had reached the "end point" of over 90% of voters choosing either the Tories or Labour. "We are now at this point of multi-polar politics".
Hunt was speaking as both Labour and the Tories nervously eye the surge in support for Ukip. Nigel Farage secured his first elected MP earlier this month when Tory defector Douglas Carswell won the Clacton by-election. Mark Reckless, another Tory defector, is also hopeful of winning the Rochester by-election in November.
Hunt warned that all three main established parties were being hurt by Farage. "Parties are losing votes to Ukip in different parts of the country, weirdly, even the Lib Dems."
He said this was in part due to the "relative abilities of Farage and his party at the moment". Hunt said the Ukip leader was "a very successful politician" who had "developed a very successful brand" but ran his party in a very "traditional" manner.
Hunt added he saw a conflict coming between the libertarian Carswell and the "nativism" of the Ukip core. "All this nice Douglas Carswell crowd-sourcing stuff, we'll see how long that lasts in Ukip."