The starting pistol has been fired and the country will be going to the polls by Christmas. But where will Britain’s election be won or lost?

Analysis carried out by Onward, the centre-right think tank, shows that the key battleground for Boris and Corbyn will be in northern towns with a proud Rugby League tradition. “Workington Man” – a typically older, White, Leave-voting man who didn’t go to university, named after the Cumbrian coastal constituency where they are most concentrated – is the new archetypal swing voter whose support the Conservatives need to win to secure a majority.

It is a sign of the scale of Britain’s post-Brexit political realignment – Workington has never returned a Tory at a general election, and Labour held it with a majority of 3,925 in 2017 – and indicative of a wider attitudinal sea-change away from the liberalising politics of the post-War era and towards a desire for greater security and a sense of belonging.

But there is another side to this. As campaigners advance northwards, the Conservative Party would do well to guard its southern flank. Constituencies in the Tories’ leafy Southern heartlands, a swathe of London boroughs, and Theresa May and Ruth Davidson’s 2017 gains in Scotland are vulnerable to the Liberal Democrats, Labour and SNP.