Polls have opened for midterm local and regional elections on Thursday that could deliver a heavy blow to embattled British Prime Minister Keir Starmer . Starmer’s center-left Labour Party is bracing for big losses in voting that will choose about 5,000 local councilors and a handful of mayors across England, as well as semi-autonomous parliaments in Scotland and Wales. Polls open at 7 a.m. and close at 10 p.m. Some local authorities will count ballots overnight, but the bulk of the results are likely to be declared on Friday afternoon. Local elections usually focus on issues like garbage collection, graffiti and potholes, but Starmer’s opponents have painted Thursday's vote as a referendum on the prime minister. A rout could trigger moves by restive Labour lawmakers to oust a leader who led them to power less than two years ago. Even if Starmer survives for now, many analysts doubt he will lead the party into the next national election, which must be held by 2029.…