I listed recently the many narratives that are already shaping the election campaign. One of the most popular, perhaps because it involves only one victim, is the so-called impending demise of the Liberal Democrats.

But just how many Lib Dem MPs are at risk at the election? In my latest prediction, I plumped for what I think is a rather modest cull of 20. Other sites, as I noted, have gone higher. To get a more rounded idea of what might happen to the party on polling day, I’ve taken a look at the majorities of every current Lib Dem MP. I’ve then grouped the MPs into half a dozen categories. These are the six species of Lib Dem MP, and at least one – if not more – will be rendered extinct come 7 May.

1

First, the untouchables. These are the MPs with the biggest majorities and who have absolutely nothing to fear. Their re-election is (barring some personal calamity or freak arithmetical occurrence) guaranteed. Rather handily for the party, this group includes top brass such as Nick Clegg, Danny Alexander, Vince Cable, David Laws and Tim Farron, along with former leader Charles Kennedy. The seats of veterans Menzies Campbell and Don Foster are also on the list; both are standing down in 2015.

(The asterisk denotes seats where the incumbent is standing down)

2

Next, the dependables. These are MPs who should all be re-elected, but whose majorities aren’t quite large enough to take victory totally for granted. I don’t anticipate any of these seats changing hands, though both Hazel Grove and Gordon are being contested by new Lib Dem candidates who may find it a close run thing. Again, we’ve some well-known names in this group: Ed Davey, Simon Hughes and Norman Baker.

3

The next group I’m calling the dicey. We’re now into territory that could well change hands, but in which the outcome is up for grabs and where a number of Lib Dems could well hang on. I think the likes of Martin Horwood in Cheltenham and Lynne Featherstone in Hornsey & Wood Green are at far greater risk than, say, Tom Brake in Carshalton & Wallington. These are seats that would all fall to another party on a landslide swing, which I don’t think we’ll see in 2015.

4

Welcome to the condemned: my fourth species of Lib Dem. These are people who are in severe danger of losing their seat, and for whom the battle to win re-election will be incredibly tough – if not impossible. There will be new candidates taking the place of Alan Beith and Ian Swales, and those two seats may be among the toughest to defend. I can well imagine all the constituencies on this list slipping from the Lib Dems’ hands.

5

The people in my fifth category might as well start packing their bags. In the case of Annette Brooke and Sarah Teather, they already have. These are the doomed: Lib Dem MPs who have no chance of surviving. Their fortunes have already been writ; their fate sealed. I don’t expect any of these people to be MPs in the next parliament.

6

And so to my sixth and final category. Here there is some cheer for Nick Clegg and co, for these are the MPs who may defy the swing, buck the trend and cling on. They include Paul Burstow in Sutton & Cheam, who I suspect will survive despite a majority of just 1,608, thanks in part to local support and a weak Tory opposition. Mike Thornton won Eastleigh in the 2013 by-election and ought to hold on in 2015, again thanks to a strong local organisation. The other four are in Scotland, where the Lib Dems will benefit whenever their closest challenger is a Conservative.

It’s worth noting that even if the Lib Dems lose every single person in my doomed and condemned categories, they will still have roughly two-thirds of the MPs they won in 2010. By no stretch of imagination could this be called a wipe-out. If the party manages expectations carefully, it might even feel like a “good” result.