There will be 650 seats up for grabs when the country eventually goes to the polls. Boris Johnson’s hopes of winning a secure overall majority are likely to rest on what happens in fewer than 80 of them. For it is in these seats that the psephological challenge facing the prime minister will be played out.

Elections in Britain are often thought of as a battle between the Conservatives and Labour. However, the most immediate threat to the realisation of Mr Johnson’s ambition does not come from Jeremy Corbyn. Rather it comes from the Liberal Democrats and the SNP.

At 18 per cent on average in the polls, up ten points on 2017, the Liberal Democrats have recovered from the disastrous drop in their popularity