I don’t even think that will do it.
England as a nation has a centre right view outside of Manchester and London.
Scotland is centre left but they have turned against Labour and support the SNP.
NI is obviously an entirely different kettle of fish.
Which leaves Wales as the only viable home nation where Labour can win.
Of course who wins what country doesn’t matter in Westminster as it’s number of seats but Labour aren’t going to win enough seats in the vast majority of the UK to form a government.
The next election will likely be the same outcome as the last.
Only way I see anything other than a Tory victory is if an anti-Tory coalition be formed and come across as credible. More people don't vote Tory than do, so it's got legs as an idea, but needs work that no one has been prepared to put in before.