Success for the Conservatives today in the Newark by-election will be in part down to forward planning.

The events causing the election had been long anticipated; the candidate Robert Jenrick had been picked months ago; a campaign team was able to develop a comprehensive plan for the constituency; and all the leaflets and posters were ready to go weeks before the contest was called.

These kinds of tactics will be vital for the Tories when fighting to save their most vulnerable MPs in next year’s general election. But there is a problem, and it is two-fold.

First: there are just so many vulnerable MPs that need defending; and second, none of them have ever fought for re-election before.

Every single one of the the party’s most precarious MPs (by which I mean those with a majority of less than 1,000) only became an MP at the last election in 2010.

Here’s the full list, ranked by majority, starting with the smallest:

1. Dan Byles, Warwickshire North (majority 54)
2. George Eustice, Camborne and Redruth (66)
3. Jackie Doyle-Price, Thurrock (92)
4. Matthew Offord, Hendon (106)
5. Nicola Blackwood, Oxford West and Abingdon (176)
[6. Cardiff North; sitting MP Jonathan Evans (194) is standing down]
7. Mark Spencer, Sherwood (214)
8. James Wharton, Stockton South (332)
9. Eric Ollerenshaw, Lancaster and Fleetwood (333)
10. Anna Soubry, Broxtowe (389)
11. Sarah Newton, Truro and Falmouth (435)
12. Nigel Mills, Amber Valley (536)
13. Paul Uppal, Wolverhampton South West (691)
14. Peter Aldous, Waveney (769)
15. John Stevenson, Carlisle (853)
16. David Morris, Morecambe and Lunesdale (866)
17. Graham Evans, Weaver Vale (991)

That’s an awfully long list of MPs with a majority under 1,000.

In their favour, you could say they’ll have had a full five years to prepare for the challenge of getting re-elected. But to have so many of your most marginal seats in the hands of one-termers will be of concern to Conservative Central Office. And if it isn’t, it should be.

The one exception in that list is Jonathan Evans, who is standing down as MP for Cardiff North. His successor as candidate is Craig Williams, who has to defend a marginal seat from a standing start. Still, he’s got 11 more months to get himself dug in. For everyone else, it’s potentially the longest of long goodbyes, shuttling repeatedly between their constituency and Westminster.

The lucky ones will have at least one to go back to on the morning of 8 May 2015. The unlucky ones will have neither.