As we all start to catch up on a bit of sleep and peruse the results in more detail, this is the point at which it’s important to start teasing out the different factors that were at play in the election.

A major question which is crucial to the future direction of Tory campaigns (and to which I don’t yet know the answer) is how the ground war played out. I wrote yesterday that the Conservatives and Labour were engaged in a battle of different approaches to the ground war. Did one (or either) work?

We know that Labour’s bludgeon – speaking consistently to more people than the Conservatives in battleground seats – proved ineffective. Whether they were saying the wrong things or using their time inefficiently by speaking to people whose minds were already made up, there are no signs that the much-vaunted millions of conversations made much difference.

But did the Tory rapier – focusing resources in on the 40/40 seats, and then focusing further within those seats on they key swing voters with hyper-targeted messaging – seal the deal either? This ground war undoubtedly will have swung some people, but the trend for strong Tory performances in seats well beyond the boundaries of the 40/40 suggests that there were other compelling influences at work on voters as well.

Chief among these is the air war – and its central message of “a Labour government, propped up by the SNP”. That was well-aimed and well-deployed – much credit goes to Lynton Crosby for his work developing it and his perseverance in ignoring the moans that it was too nasty. Either the research of high command was better than that of the pollsters, or their gut instincts told them the data was wrong – either way, their good call evidently won a lot of votes.

The important but difficult thing will be to work out how many were won by that air war, and how many were swayed by the targeting programme.

It’s important because we need to identify and develop the best bits of each to continue rebuilding our campaign machine – simply assuming that we won, so the whole suite of arguments and tactics are all good, would be an error. It would be wrong to frame this as a question of either air war or ground war – you need a good national message and a strong local game to win elections. But we will best serve our cause by robustly scrutinising both, in order to further improve them.

It will be difficult to do because this election’s first victim was the reputation of political polling. To properly examine what worked and what didn’t, we must be sure the data we use is accurate and complete. Evidently large amounts of the available data isn’t that reliable – which could prove a bit tricky.