Sir Keir Starmer is facing the biggest test of public opinion since the general election in 2024 (PA) Millions of voters are heading to the polls on Thursday for the Scottish and Welsh parliaments, as well as for local councils across England. Sir Keir Starmer is facing the prospect of losing hundreds of council seats, as well as Labour ’s dominance in the Welsh parliament, the Senedd, in the biggest test of public opinion since the general election in 2024. The latest YouGov poll shows that Labour’s 27-year rule in Wales is set to end with the party predicted to fall to third place , with Plaid Cymru taking the lead and Nigel Farage’s Reform UK coming in second. MPs are reportedly moving to oust the prime minister in the wake of the elections, in a bloodless coup modelled on the way Sir Tony Blair was encouraged to make way for his successor Gordon Brown.…