These Cheshire voters will choose a new MP and set the course of British politics for the next four years

When a government has a working majority as large as Labour’s and probably four years still to run in office, a tricky early byelection may seem a relatively minor distraction. Yet the expected byelection in Runcorn and Helsby is freighted with significance. This first big electoral test for Sir Keir Starmer’s government could also become one of its defining political moments.

Labour is on the back foot as the byelection looms. The party is well down in the polls, Sir Keir’s ratings are poor, and a mere 19% of the public approve of the government’s record. The byelection, likely to take place alongside the local elections on the resonant date of 1 May, will follow a government spring economic statement that is expected to signal bleak financial forecasts, unpopular new spending cuts and bitter internal divisions.