There are just over 70,000 electors in Oldham West and Royton. Of those around 11,000 are postal voters. On a turnout between 30% and 40%, that equates to between 21,000 and 28,000 votes to be cast on Thursday. The electorate is split into three distinct groups, as the map below shows.

Oldham West and Royton. Source: Election Data/Ian Warren

First are the south Asian communities, around 20% of the electorate in Oldham West, or around 14,000 voters. As the map shows they are clustered in the centre of the seat in the wards of Coldhurst and Werneth. In recent local elections they have voted Labour and will do so again. However their turnout record is low, which is one reason Labour is working so hard to mobilise it. The local Asian councillors are working together well, which should give Labour some hope the vote will come out. Also worth noting is that this group will vote by post at higher levels than others in the seat, so it’s likely Labour has a lead in the postal votes as we stand.

Second are the middle-income households along the western perimeter of the seat, again accounting for around 20% of the electorate, or around 14,000 voters. They’re going to break for the Conservatives or Ukip. Nigel Farage has said he will personally target these voters, and for good reason. If Ukip can compete with the Conservatives, or even beat them, among these households they go some way to offsetting any losses they incur from the Asian vote. These households are civic-minded and have very good turnout records in local elections, so it’s going to be essential for Ukip to pile up the vote here.

Whichever way you shake down the numbers, Labour will come out of the Asian and Tory households with a lead. It could be as little as 1,000 or it could be 3,000. The problem for Labour is that it is going to need that lead because the remainder of the seat is comprised solely of the white working classes, which account for around 60% of voters (around 40,000 votes).

The white working classes in Oldham break into two distinct groups, each with their own reasons for moving from Labour to Ukip. First are the blue-collar working households. They have conservative views on immigration, welfare and defence. They have seen Oldham transformed before their eyes during their lifetime and they don’t much like the change. They have Labour values but have watched Labour move further and further away from them, both literally and metaphorically. In the late 1990s Labour stopped working in too many wards across the country as it pursued, probably rightly, votes elsewhere. It also seemed to ignore or not comprehend the level of worry about immigration in places like Oldham as it further opened the doors to the EU accession countries in 2003.

The second group within the white working classes are deprived and disaffected younger or middle-aged voters who have suffered the most as a result of the economic downturn in the town. They choose to vote for Ukip as a means of expressing their contempt for Labour and the political establishment. They don’t like politicians; they believe politicians are only in it for themselves and that they don’t care what their constituents think. They believe, rightly or wrongly, that Labour has done precious little to help them. They don’t turn out for elections as they believe doing so is futile. Ukip has given them a reason to turn out: to deliver a kick in the groin to Labour and the political establishment.

Unfortunately for Labour, both these white working-class groups have reasons to despise Jeremy Corbyn, which is what they are expressing on doorstep after doorstep. Blue-collar households think he’s soft on immigration and welfare and a republican pacifist. Disaffected voters either don’t know who he is, in which case he’s “just another politician”, or hear him speaking about socialism and solidarity and wonder what he’s blathering on about. Both groups will know full well what his and John McDonnell’s views on the IRA are. Both groups aren’t shy in hanging St George’s flags from their windows, as Emily Thornberry might note. All of which is good reason for Corbyn cancelling seat visits and concentrating on a good local candidate in Jim McMahon.

This gives Ukip an opening. It will need to beat Labour among the white working classes while competing strongly with the Conservatives. Will it do so? Labour is certainly nervous. Its vote is soft, something that sends a chill up its spine. Labour canvassers and candidates will know all too well that such softness often leads to people staying at home. Then there are the “don’t knows”. They hate Corbyn, and Labour will worry that enough of them will express that sentiment by voting Ukip.

Most troubling for Labour is the fact that in byelections all the swing happens in the last five days as voters’ minds are concentrated on what is before them. If Ukip has already made significant inroads into the Labour lead, then the next five days will only confirm this trend.