The main points that emerge from Shipman's colossal research effort are as follows:
- The Leave side suffered from deep and acrimonious divisions. There was the broadly respectable Vote Leave organisation, which was eventually designated by the Electoral Commission as the official campaign. Vote Leave was run by Dominic Cummings, a brilliant but intolerant individual who was described by David Cameron as a "career psychopath". He survived an attempt to fire him by his own board. Then there was Leave.eu, the Ukip-linked campaign run by the dislikeable Arron Banks, which was less squeamish about exploiting the immigration issue: these were the guys who produced the infamous "Breaking Point" poster. As if two feuding organisations weren't enough, there were also separate groups called Grassroots Out and Labour Leave.
- All was not well on the Remain side either. David Cameron didn't push his renegotiation to the wire, and the resulting deal was so feeble that Stronger In deliberately avoided mentioning it during the campaign. Remain campaigners seem to have pulled their punches at various times in order not to worsen the poisonous atmosphere inside the Tory Party with "blue on blue" attacks. They also stuck doggedly to their script on the economy and failed to engage the Leave side sufficiently on immigration. Stronger In's official, cautiously favourable, line on immigration was ignored by Remain politicians until the very end of the campaign, when Ruth Davidson and Sadiq Khan deployed it to widespread acclaim in the Wembley debate. Worse, the claims of economic calamity which made up the Remain message were designed to appeal to middle-class Conservative voters, not to the poorer, northern-based Labour supporters who swung the result for Leave. One campaigner observed:
When we started just saying "The economy will be fucked," it showed what a profound misunderstanding they had of Labour motives. Across the north-east and the north-west people already felt like the economy was pretty fucked and not working for them. It was just a Tory voter strategy.
- Shipman attacks the consensus view that Boris Johnson joined the Leave campaign out of opportunism in order to increase his chances of becoming prime minister. If Shipman's sources are to be believed, the truth is much worse - Johnson really believes in the Brexit cause. He emerges from the book as a more erratic and less ruthless individual than one might imagine.
- One man who does come out of the book as a villain is Jeremy Corbyn: it seems that Corbyn and the people around him deliberately and culpably withheld their support from the Remain campaign. Shipman recalls that Corbyn had spent years denouncing the EU as a capitalist club, but he also reveals that he had a tactical reason for his misbehaviour. If Remain won - so he calculated - he would be able to share the credit as a nominal Remainer; but if Leave won, people would remember his lukewarmness and conclude that he had had his finger on the pulse all along.
- Most ominously of all, Theresa May emerges as a weak and vacillating figure. During Cameron's renegotiation, she alternated between pushing hard for new immigration controls and pulling back for fear of annoying the Germans. She seems to have fallen into line behind Remain because it was an easy default option, and her only major speech of the campaign was an unmemorable and ambivalent effort. She accrued support in the leadership campaign, in part at least, on the basis that she wasn't Boris Johnson. Shipman records how she neatly appropriated Ken Clarke's description of her as a "bloody difficult woman" - "the next person to find that out will be Jean-Claude Juncker". But he hasn't found that out, has he? That's the point.