OK, so let’s recap: 650 seats up for grabs, about 85% in England, Labour currently holding 345, the Tories 193, the Lib-Dems 63, various others 32, Northern Ireland 18. A swing of 1.5%? ends Labour’s majority, a 4.5% swing loses its largest party status, and a uniform 7% swing gives the Conservatives a majority at around 325 seats.

But even in Australia’s preferential system — which smoothes out anomalous votes in individual seats (because swings away from the incumbent party will always either come back to it, or to its major opponent) — a forecast is something of an over simplification.

In a three and a half party system — the current votes are approximately Labour/Con/Lib-Dem, 36.5/33.5/22.5/7.5 (other) — it becomes an abstraction pure and simple, one that you hope points in the general direction of the eventual result.

So there’s many particular factors to be brought into account.

The first is that the current parliament is a mess of minor parties. First off is the Liberal-Democrats, who, at 63 seats, hang between major and minor party status. Principally, this is the old Liberal Party, which was a major party until the First World War, collapsed to 12 seats in 1945, and almost went out backwards with six seats total in 1970. They began to creep back slowly, and received a boost in 1988 when they combined with the SDP, the Social Democratic Party that had split from Labour in 1981.

For several decades the Libs were the voice for free trade and civil liberties (to a degree), although much of the latter agenda was taken over by Labour in the ’60s — and then given back with New Labour in the ’90s.

Before their mid-century collapse, the Lib-Dems had strongholds in the West Country and rural Scotland, and Wales — areas where they effectively had become the secular version of non-conformist protestantism. They have since regained these areas to a degree, while also picking up a range of inner city seats dominated by “new” class managerial types. The rural members tend to have to adopt a centre-right all-rounder perspective to keep their voting bloc together, the inner-city members have to go socially to the left.

On top of that, there is a split between two ideological groups: the “Orange Book” liberals — including leader Nick Clegg and deputy Vince Cable who tend towards the free market, with social market social policies — and the Beveridge Group, social liberals who command about two-thirds of the MPs.

Effectively that means that the entire Australian political spectrum is contained within a single party, a political snow dome.

The next mob down are the two Great Britain* nationalist parties — the Scottish Nationalist Party with seven, and Plaid Cymru in Wales with three. The SNP are aiming to take two new seats from Labour, one of them a virtual certainty. Plaid can take two Labour seats with a 1.8% swing.

After that, it gets weirder on GB. The nearest thing approaching a party is Respect, the outfit created by a coalition of the Socialist Workers Party and British-Asian community groups in London and Birmingham. They took Bethnal Green from Labour with George Galloway at their head — and then, surprise, surprise, the party split down the middle, and the SWP departed. They are recontesting Bethnal Green with a new member, Galloway is running for Poplar next door, and they’re also going for a Birmingham seat.

The Green Party, which can take 6-8% of the national vote, don’t have a single seat in the UK parliament. But they’re hoping to take Brighton Pavilion, which is like St Kilda on steroids, or Prozac. The Green Party is third there, with 9500 votes out of 40,000 turnout — if it can take 2000 from Labour’s 15,000 and 2000 from the Lib-Dems then party leader Caroline Lucas could get up.

The British National Party, and a bored media, claim they have a chance in Barking — but with Labour on 13,000 and the BNP on 5000, it would have to double its vote solely from Labour take-aways or equivalent to be in with a chance. The anger with Labour in the now destroyed industrial area of Dagenham may well be enough to do the trick, however.

The UK Independence Party, an incredible collection of blue-blazered old duffers who look like David Niven residing at a seaside hotel, have no seats, but gained 16% at the European elections and have 12 MEPs. However, their closest cooee in the UK is in Norwich North, with 4000 against the Tories’ 13,000 winning result — so no real chance of toppling them. Even more predictably weirdly, one Tory MP claimed to have defected to them. When informed that they had no party status to defect to, he deined he’d ever tried to do so.

The weirdest party by far has to be Kidderminster Hospital Health Concern, which has held the West Country Wye Forest seat through two elections. The party was formed around an independent standing against the local member to protest closure of the hospital’s casualty department. What’s really weird is that the party has now begun to win local government seats increasingly far away from Kidderminster. I mean, not Norfolk or anything, but kind of distant. They’ll probably lose the seat back to the Tories though.

There’s one other genuine independent: Dai Davies, who took the traditional Labour seat of Blanau Gwent (held by Nye Bevan and Michael Foot), and is left of Labour.

Of course, in Ireland, things work on a completely different basis.

Here the 18 seats are shared out by three parties and an independent — on the nationalist/republican side Sinn Fein has five and the moderate SDLP three. On the loyalist side, the Democratic Unionist Party has eight, there’s one independent who was the Ulster Unionist Party’s sole member until last week, and there’s one seat vacant.

Sinn Fein are the political wing of the now-disbanded IRA — ha ha ha —  and the DUP were attached to loyalist paramilitary groups. Over the past decade or so, both have squeezed out their moderate rivals — the SDLP and UUP respectively — and they aren’t about to give up now. That creates a weird situation whereby each national bloc is split, and thus two of the SDLP’s seats are vulnerable to the Unionists, one Sinn Fein seat may fall to the DUP, and the UUP and DUP are fighting over Antrim South.

Sinn Fein neither votes nor takes its seats — making the actual parliament 645-646 — and the Tories, despite some political footsy, could not bring themselves to transfer their connection with the UUP to the DUP.

For the most part, of course, the minor parties won’t matter at all. Most likely the major fight will be within the Lib-Dems around competing principles — under what conditions could they support the Tories, and alternatively, could they reasonably support a minority Labour party? Since this will be matter of the leadership taking a case to their members and submitting it to the vote, it promises to be a torrid tussle —  especially if a few Lib-Dem MPs could be tempted away in a tight situation, with promises of ministries, hookers, etc.

Scenario two — if the Conservatives get about 39.5% of the vote, and get to about 305 seats, could they stitch up a deal the SNP, Cymru, Health Concern, and 8-10 unionist MPs? That would create a furore over dealing with DUP, and would mean selling their soul to the nationalist parties, but it is not impossible.

Scenario three — Labour is about 70 seats short of a majority at 250 (having had a swing against of 6%) — they govern with the support of Lib-Dems, SNP, PC, Respect, SDLP and independents.

Of course, one might say that no one would accept scenario tow or three in their right mind. But, of course, power is power is power, and it is not impossible that in the end, the next government will rise or fall on whether Kidderminster has her way.

*Great Britain remember is the name of the island. The UK is of Great Britain and Northern Ireland. Ireland is technically Lesser Britain or Little Britain, amazingly not much used.