Labour MP Catherine West threatens to collect signatures for a leadership contest by Monday after Starmer loses 1,400 council seats

Catherine West, the Labour MP for Hornsey and Friern Barnet and a former junior Foreign Office minister, told the BBC's PM programme that she will move to collect signatures from the Parliamentary Labour Party for a leadership contest if no cabinet minister has openly challenged Keir Starmer by Monday morning. "I'm putting people on notice – if I don't hear by Monday morning of some leadership hopefuls, I will be asking everybody in the Parliamentary Labour Party to put a name against my name, because we need to get this ball rolling," she said. Her preferred option, she added, was for the cabinet to handle it through a reshuffle: "where there's plenty of talent and for Keir to be given a different role, which he might enjoy, perhaps an international role, and then for others to come to the fore."

The threat lands at the end of a council count that has stripped Labour of more than 1,400 representatives from English councils. Reform UK has taken Calderdale, Wakefield and Leeds from Labour and ended more than 50 years of Labour rule in Barnsley. In Bradford, Reform UK was on track to be the largest party with 29 of the first 75 seats declared, against 18 for the Conservatives and 15 for Labour. In Croydon, neither Labour (30 seats) nor the Conservatives (27) reached the 36 needed for a majority; the Greens won 8, with two seats each for Reform UK and the Liberal Democrats.

Welsh Labour has lost First Minister Baroness Eluned Morgan's seat in the Senedd; she resigned the leadership the day before. Ken Skates, first elected in 2011 and a former Welsh transport secretary and economy and infrastructure secretary who was re-elected for Fflint Wrecsam, will serve as interim leader until a timetable is set for a full election. "Today is just the beginning of a process that will help us to understand what we got wrong. Because we did get it wrong," Skates said. Welsh Secretary Jo Stevens praised Skates's "determination, experience, and values" and pointed to their joint work on the UK Labour Government's £14 billion rail plan for Wales. Starmer himself thanked Skates for "stepping up to provide leadership for Labour in Wales and the Senedd as we begin a period of necessary reflection and rebuilding."

In Scotland, Scottish Labour leader Anas Sarwar conceded defeat on Friday afternoon at the Glasgow count before the full scale of losses was clear. By the time regional results were finalised after 1am, Scottish Labour had tied in second place behind the SNP with Reform UK — a party SNP leader John Swinney has called an acute threat to devolution. Veteran Labour politicians described it to the Guardian as a defeat made in Downing Street.

There was a second piece of unwelcome news for the government on Saturday: the National Education Union, the largest teaching union in England, voted at its national executive to hold a formal strike ballot later this year over pay and school funding. The union opted to delay opening the ballot until the autumn term. General secretary Daniel Kebede said: "The cracks in our education system are obvious to all. Schools are running on empty. Pay and workload issues are driving many out of the profession, resulting in a recruitment and retention crisis that is directly impacting on the education of our children and young people." He said the government had to "step up and deliver the properly funded education system our children and young people deserve."