Transport Secretary Heidi Alexander publicly asked Keir Starmer on 20 June to say when he plans to leave office. She is the most senior minister to make this call, adding weight to a quiet campaign inside the Labour Party for an orderly change of leadership.

Alexander's move comes after Andy Burnham won a by-election in Greater Manchester by a large margin — a local election triggered when a seat becomes vacant. Burnham is the mayor of Greater Manchester and influential within Labour's moderate-left wing. His strong result has intensified calls for Starmer to go.

Alexander is not alone. Other senior Labour figures have already made similar calls. Atul Mahmood, another minister, had already asked the Prime Minister to set a date back in May. By that point, 72 Labour MPs had either demanded Starmer's resignation or asked him to announce a departure date. More have likely joined since.

Why the pressure is building

Trouble inside the Labour Party did not appear overnight. Ministers have quit, election results have disappointed, and questions about the party's direction have mounted. These problems have worn away the loyalty that normally protects a sitting prime minister from his own MPs. When Cabinet ministers start saying what backbenchers have been whispering in corridors, the political situation changes.

Starmer's decision to appoint Peter Mandelson as US ambassador earlier this year added frustration. Labour MPs expressed anger at the appointment — Mandelson represents a part of Labour's past that many in the party have tried to move beyond.

The exact words matter. Alexander and Mahmood are not asking for Starmer to leave tomorrow. They are asking him to set a "timetable" — a specific political term that lets a prime minister step down with some dignity while admitting that departure is coming. This language usually appears when leadership change seems certain but the timing is still being worked out. It also sidesteps Labour's formal leadership election rules.

What Starmer does next will shape everything. Prime ministers who announce a departure date under pressure often find that the pressure does not ease; it gets worse. When Tony Blair announced his departure date in 2007, his authority drained from Number 10 almost immediately.

One more complication: Burnham's success is a reminder that Labour's strongest performers are not in Westminster right now. Whoever replaces Starmer will need to keep the party's MPs united, reconnect with the voters who gave Labour a landslide not long ago, and avoid a damaging fight with Starmer that helps the Conservatives. That is not easy. The people pushing for a timetable do not all agree on who should come next.