Daily catch-up: a look back at the general election of 2015 – why Labour lost and the polls got it wrong

Genuine sign in TK Maxx, spotted by Memphis Barker. Welcome back to the Catch-Up Service. The Labour Party starts the year as it means to go on.

• I wrote about what we might expect from the inquest into the opinion polls' failure at the general election, to be published in two weeks' time, in The Independent on Sunday yesterday. Part of the problem was one of sampling – too many politically engaged young people and not enough over-75s, with lower-income respondents saying they were more likely to turn out to vote than they actually were. But that doesn't explain why the polls were so accurate in 2010: it seems unlikely that this sampling error arose over just five years.

Something else is going on, which I would put under the heading of "politics" or "people making up their minds at the last moment". In 2010, I think this favoured Labour, because voters took fright at Conservative plans to cut public spending. In 2015 it strongly favoured the Tories, because of the three questions of leadership, the economy and fear of the SNP.

It is curious that, so far, the inquiries into the polls have not picked up much sign of late swing. I know of two people who intended to vote Lib Dem but decided to vote Conservative on the way to the polling station, one of whom I mentioned here. Yesterday, Padraig Mckenna, who supervised some of the counting of votes as a party agent, told me he saw several instances of where voters had changed their minds: ‏"Original vote for other candidate crossed out and a clear final vote for Tory." (One of the tasks of party observers is to check the returning officer's decision to accept irregularly marked ballot papers where the intention of the voter is clear.) It will be interesting to see what Professor Patrick Sturgis says about that on 19 January.

• Peter Mandelson reviewed Philip Cowley and Dennis Kavanagh's The British General Election of 2015 for The Independent on Sunday. He quotes the party's own internal poll findings to support his argument that the election was winnable but that Ed Miliband's "insipid gesture politics" and his lack of credibility on the economy lost it. I am not sure if he is referring to the "2105: What Happened?" report written immediately after the election, and referred to on pages 268 and 367 of the book, but I understand that Cowley and Kavanagh's account of this document, which is unlikely to see the light of day for some time, is understated.

• And finally, thanks to Internet Hippo for this:

"I’m doing a book signing at Barnes & Noble today. Nobody asked me to. It’s not even my book."