At an event at King’s College last night, Ed Balls presented an apparent paradox: "The best thing for Theresa May would be for the Labour Party to get a grip on itself.” But speaking with the wisdom of experience, Balls explained: “It was terrible for us that Iain Duncan Smith became leader of the Conservative Party."

The lack of opposition, he said, intensified Labour’s internal divisions. "A strongly led Conservative Party in 2001 would have been the best thing that could have happened to us. The overriding story became Blair-Brown and the succession. Everything was seen through the prism of Blair versus Brown and who was going to succeed him, Brown or someone from the Blair camp."

Balls, who is a King’s College visiting professor, and who was promoting his fine new memoir Speaking Out, argued that May was making a mistake by "not defining Brexit" and by "trying to allow a bit of chaos and stand above fighting ministers".

On Labour’s plight, Balls said that a split would be "massively premature" (not a complete rejection) and suggested that, as in the past, it would take further general election defeats before the left’s opponents could win.

"In the end, if you go back to 1994, when Tony became leader of the Labour Party there was a subsequent big increase in membership and maybe they would have been people who were more New Labour in their leanings. But the reality is that in 1994, that process hadn’t happened, the Labour Party membership was not the same as today’s membership, but it was a membership which was quite demanding, probably more to the left than the equilibrium of the Parliament Labour Party. But we’d lost three general elections and people really wanted to win and Tony Blair won by a landslide in that election because people wanted a victory.

"Now, we haven’t had a general election defeat since Jeremy Corbyn became the leader, we’ve only had one general election defeat so far since we came out of government. So maybe there has to be a focusing of some people’s minds on the choice between government and opposition and the kind of change we saw in the attitude of members between the mid-1980s and the early 1990s, that may be part of it."

Balls also made a coded criticism of Owen Smith’s campaign warning that “it’s not enough to say we agree with Jeremy but we don’t like his leadership style.” He called for “a galvanising choice” about the party’s direction, one that Corbyn’s opponents could "recruit around".

"I think there are some bigger choices about where our country goes, which we talked about earlier for Theresa May, which are as relevant to the Labour Party about our attitude to markets, our attitude to business, our attitude to Europe, our attitude to defence and security. I think we have to have those arguments and use them to galvanise people who have a more centre-left, social democratic view of the future of our party than some of the people who have joined the Labour Party over the last year."

Asked whether he could make a political comeback (Balls, like David Cameron, is only 49), he was careful not to rule out the possibility. But he quipped: "The chance of Labour’s NEC picking me as a by-election candidate is pretty thin."