Ms Nandy, who according to the Oddschecker website is currently third favourite to take the helm of her party from Jeremy Corbyn, voted for Boris Johnson’s deal at its first appearance in Parliament in October.
But the Wigan MP has now backtracked, saying there is now no chance of Labour MPs negotiating access to the customs union due to a large Tory majority following last week’s general election.
“I think it’s very unlikely I’ll vote for it this time,” she told Sky News on Wednesday. “I did vote for it last time. There were 19 Labour MPs who did and that’s the reason it got through.
“I’m minded to make a different decision this time, not because I’ve changed my mind on the fact we’re leaving – it’s clear now we are leaving and the public has given us a very strong message to that effect – but because last time round I thought there was a genuine prospect of having some kind of cross-party cooperation and potentially winning a customs union.”
Ms Nandy’s stance, while guaranteed to make no difference to the outcome on Friday due to the Tory majority, could frustrate constituents who backed Leave by 64% in the 2016 referendum.
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But she said the lack of opportunity for a customs union will harm the town, saying: “It is really important in towns like Wigan, because we have the Heinz factory [and] many food manufacturers there. We also have service companies that have access to the single market.
“I’ve spoken to people on the other side this time round, asking them what they think the prospects are. I texted one cabinet minister and his answer was ‘zero’.”
Ms Nandy has yet to declare her candidacy but is widely expected to run after a flurry of media appearances since Labour’s general election disaster.
Her speech nominating Lindsay Hoyle as Commons speaker on Tuesday was also widely perceived to be a leadership pitch.
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