Keir Starmer has insisted the UK will not rejoin either the EU, the single market or the customs union within his lifetime, in his firmest pledge yet that Labour will not seek much closer relations with Europe for as long as he is prime minister. The Labour leader told reporters on Wednesday he did not think Britain would go back into any of the three blocs while he was alive, all but ruling out rejoining even if he wins a second term in office. In recent days, the Labour leader has begun talking more freely about what his party would do in power, as polls continue to suggest it is heading for a landslide victory. He also said on Wednesday, for example, that he would seek to extend the parliamentary timetable immediately after the election to allow more time to legislate before the summer. With less than 24 hours to go until polls open, Starmer has largely avoided talking about relations with the EU during the campaign, as Labour seeks to avoid the mistakes it made in 2019 when it alienated leave voters by promising a second referendum. Some have suggested this reluctance to talk about the issue masked a desire to pursue re-entry to the customs union or single market during a second Labour term, something other senior figures in the party have failed to rule out. Starmer insisted on Wednesday, however, this was not the case. Asked whether he could see any circumstances where the UK rejoined the single market or customs union within his lifetime, Starmer said: “No. I don’t think that that is going to happen. I’ve been really clear about not rejoining the EU, the single market or the customs union – or [allowing a] return to freedom of movement.” He repeated, however, his view that Labour could achieve better trading arrangements with the EU in certain industries. “I do think we could get a better deal than the botched deal we got under Boris Johnson on the trading front, in research and development and on security,” he said. Starmer spent his final day on the campaign trail travelling around the UK, starting with a stop in south Wales attended by dozens of Labour activists and candidates. On the subject of a legislative programme, he said: “How much legislation we will be through by the end of July I think is questionable, because the timetable is very tight, although it seems obvious to me that we’ll have to extend the timetable. We will be working very hard.” Starmer’s first days in office are likely to be spent battling various crises, including one in Britain’s full-up prisons, which the Institute for Government suggested on Wednesday could be alleviated by cutting average sentences. Starmer indicated he was open to such an idea, saying: “In terms of the specific things that we will do, we’ll have to wait and see what that is, but I can’t stand here and pretend to you or everybody else that we can build a prison in 24 hours after the election result is called. “We have to get on with the hard yards of sorting this mess out, but it is one massive mess.” As well as the immediate crises with which he will be grappling, Starmer has also begun to talk about the long-term challenges facing a Labour government, including taking on the threat of rightwing populism. He told reporters he saw it as part of his job as a progressive leader to combat the appeal of parties such as Reform UK, and even suggested he would be willing to work across party lines to do so. Such a scenario is playing out in France, where candidates from centre-left and centre-right parties are dropping out of the legislative election to make sure they do not stand in the way of others defeating the hard-right National Rally. Starmer said: “The very many challenges here in Europe and across the world will have to be met, in my view, by progressive answers. And it falls to us to make that argument – and to work with others to make that argument.”