Three economic heavyweights have been brought in to advise Andy Burnham as he attempts to reassure the markets before his possible return to parliament on Friday and challenge to Keir Starmer, Rowena Mason reports.

Burnham is understood to be getting advice from Andy Haldane, a former Bank of England chief economist, as well as Richard Hughes, a former chair of the Office for Budget Responsibility and Jim O’Neill, a crossbench peer and former Treasury minister who worked on George Osborne’s Northern Powerhouse.

Good evening, and welcome to the Guardian’s Makerfield byelection live blog. The polls have just closed and we may have to wait until around dawn (quite early in the summer, of course) until we get a result. But, as the votes are counted, it should become clear well before then who is going to win. Andy Burnham, the Labour former cabinet minister, current mayor of Greater Manchester, and potential future prime minister, is widely expected to be the new MP, but at this point no one knows for sure.

Here is our latest story about what has been happening today, and what may unfold in the hours to come.

This byelection has been widely described as the most consequential byelection in British history. That’s probably an over-statement, but more on that later. Nevertheless, it is definitely one for the history books, because it is expected to lead to the replacement of Keir Starmer as PM.

During the night we will get the result; ultimately democratic politics is all about numbers, and these numbers really will matter. In his Spectator cover story, Tim Shipman has a good explanation as to why.

At the time of going to print, Op Makerfield is not a totally done deal. Two of Burnham’s top team parrot the same line: ‘It’s closer than you think.’ But those advising the Manchester mayor think the scale of any win will determine the speed of events. ‘If he wins by low single digits, Keir Starmer digs in and says: “You can’t come for me until after the Manchester mayoral election on 30 July,” and it’s bloody trench warfare,’ one says. ‘If it’s a comfortable, single-digits win, the soft left will try to take power through a conversation, but they will probably discover that power has to be taken by force. If Andy gets more than Reform plus Restore combined, start the clock. There will be an avalanche.’

Voting figures are very specific but, as for what happens next, there is a lot less clarity. Overnight, and during Friday, we might get a slightly clearer idea, but it is quite possible that by this time tomorrow there will still be considerable uncertainty as to how a Burnham/Starmer power struggle may unfold. Pippa Crerar had a superb account of the state of play in her Guardian splash this morning.

Of course, it is possible Reform UK could win. That would also lead to immense turmoil for Labour – with less prospect of a positive resolution for the party.

Although we will be focusing on Makerfield, there are two other byelections tonight, in Aberdeen South, and Arbroath and Broughty Ferry. We will be covering those too.

At 11.10pm the BBC will be launching its byelection programme, hosted by Laura Kuenssberg. As for when the results will come, we’ve been told around 1.30am for Aberdeen South, around 3am to 4am for Makerfield and around the same for Arbroath and Broughty Ferry. But these estimates are never very reliable.

We hope to turn comments on in the morning. Overnight, if you want to flag something up urgently, it is best to use social media. You can reach me on Bluesky at @andrewsparrowgdn.bsky.social. The Guardian has given up posting from its official accounts on X, but individual Guardian journalists are there, I still have my account, and if you message me there at @AndrewSparrow, I will see it and respond if necessary.

I find it very helpful when readers point out mistakes, even minor typos. No error is too small to correct. And I find your questions very interesting too. I can’t promise to reply to them all, but I will try to reply to as many as I can, either BTL or sometimes in the blog.