Jeremy Corbyn may have to resign or face a revolt from MPs if Labour's performance fails to improve, Neil Kinnock has warned. In an interview with the New Statesman, the former Labour leader said it was "difficult to see" Corbyn as electable and added: "If Jeremy is seen to be failing to connect to the electorate after a reasonable space of time then he may come to his own conclusions."

Asked whether MPs should challenge Corbyn if he refused to step down, the peer said: "There’s a fundamental question here and it is whether people want to secure power in the party or to win power for the party. Those people who want to win power, whether they’re left, right or centre, will be watching the evidence and will make their decision on the basis of that evidence. Not because of some spasm of emotion, or the fact that their candidate didn’t get elected, they’ll want to know that they have a party which is being led in its advance with the electorate. If that isn’t the case then conclusions must be drawn." Labour's current poll ratings are the worst of any opposition in post-1945 history and it is forecast to become the first to lose council seats in a non-general election year since 1985.

Kinnock, who led Labour from 1983-92, advised against an imminent challenge to Corbyn, saying that "I take the view that a lot of people, left, right and centre, in parliament and in the unions take, that Jeremy Corbyn won, he’s got to have some space and he must be judged on performance in terms of Labour’s advance or movement in the other direction. That’s the political reality that people must really grasp and work on, the idea of trying to take disruptive action in the short-term will simply be fruitless, that’s the reality."

But he added that Corbyn's record of rebellion made it hard for him to command loyalty. "Jeremy's commitment to the party has never been in doubt, his commitment to various party leaderships has frequently been in doubt. That comes up in every conversation ... It’s difficult for him and those closest to him in the circumstances to acquire loyalty and to uphold unity when there’s that record stretching back 30 years. It isn’t impossible provided that he can show evidence that Labour is making advances." Corbyn is currently seeking to reverse Labour's support for Trident, making unilateral nuclear disarmament the party's policy for the first time since Kinnock abandoned the stance in 1989.

The former Labour leader was interviewed by the New Statesman as a part of a feature on whether Labour should split. Thirty five years ago this week, the Limehouse Declaration was issued by the "Gang of Four" (Roy Jenkins, David Owen, Bill Rodgers and Shirley Williams) and the Social Democratic Party was formed two months later. Kinnock, who became leader after Labour's 1983 landslide defeat, warned of a split: "Anybody advocating it has got to face the reality that they would be letting the Tories rule the 21st century just like they mainly ruled the 20th century. There can’t be any rational social democrat or democratic socialist who would want that but it is a historic inevitability if they pursue it."

But Peter Hyman, Tony Blair's former strategist and speechwriter, wrote: "Politics today is far more fluid, and people are crying out for a fresh voice in British politics. If, but only if, the Labour Party does not get back on track in the next 18 months, then there will need to be serious consideration given to a new party emerging." Labour MP Frank Field, the chair of the work and pensions select committee, argued that the parliamentary party should elect a separate leader. "Not having a leader in the country, which Jeremy is, is not our weakness. It is in having no alternative prime minister. That person will hopefully come from the 2010 intake who are not stigmatised by previous Labour regimes. Then, please God, Labour backbenchers will have the courage to act decisively."

Corbyn ally Diane Abbott, the shadow international development secretary, told the New Statesman that a split would be "a real betrayal of the millions of people in the country who need a Labour government and "a betrayal of the thousands of party members who are behind the Labour leadership." She added: "The bitter and rancorous split is amongst MPs and only amongst MPs. It’s awful that, months after winning the Labour party leadership with the biggest majority, people are still attacking the leadership."