I think the betting markets have got this right and that LAB is in with a very good chance of winning most seats at the next general election but at the moment an overall majority.is rated as an evens chance.
Ever since the complete collapse of the party in Scotland at the 2015 General Election what is now Starmer’s party has always been in a very difficult position. it will be recalled that at the 2010 general election LAB took 41 of the 59 Scottish seats. Five years later that was reduced to a single MP following the SNP surge at the 2014 Indy referendum.
Unless there is a massive recovery north of the border then it is hard to see how LAB can make sufficient gains in England that would put it above the 325 seats required for an overall majority.
An issue for the Labour Party in England is that a lot of its support is in very strong seats where it has big majorities and it is much less evenly spread than the Tory backing.
If Starmer does fall short my guess is that he would still become Prime Minister. It could be that the Labour and Lib Dem seat totals combined manage to take him above the majority threshold.
I have long thought that the Tory campaign at the next election will be a near replica of what happened in 2015 when it was all about how the SNP would be put in a powerful position if the Tories did not get a majority.