What is at stake in the Chesham and Amersham by-election on Thursday?

After a long period of drought, we are now halfway through a series of four parliamentary by-elections in quick succession. There had been no by-election since Brecon and Radnorshire in August 2019, won by Jane Dodds for the Liberal Democrats (who then lost in the general election four months later), until the Hartlepool contest last month.

Labour’s defeat in Hartlepool was significant, crystallising the view that, although Keir Starmer had started well as leader of the opposition, he is struggling to make his mark against a vaccine-boosted prime minister.

A second by-election a week later, by contrast, was barely noticed, as Anum Qaisar-Javed retained Airdrie and Shotts for the Scottish National Party after Neil Gray gave up the House of Commons for a seat in the Scottish parliament.