Jennie Formby, the Labour general secretary who was a close ally of the former leader Jeremy Corbyn, has resigned from the post, the party has announced. The move gives the party leader, Sir Keir Starmer, an opportunity to anoint a new candidate to control the party machine, and is further illustration of a major political shift since December’s general election. A statement released on behalf of Formby on Monday said: “When I applied for the role of general secretary in 2018 it was because I wanted to support Jeremy Corbyn, who inspired so many people to get involved in politics with his message of hope, equality and peace. “It has been a huge privilege to be general secretary of the largest political party in Europe for the last two years, but now we have a new leadership team it is the right time to step down. “I would like to thank Jeremy, our members and my staff colleagues who have given me so much support during what has been a very challenging period, in particular when I was suffering from ill-health. “I wish Keir and Angela the very best of luck in taking the party forward and leading Labour to victory at the next general election.” Formby, a former Unite official and close associate of Len McCluskey, took over as general secretary, the party’s most senior employee, in March 2018. She received treatment for breast cancer last year. Allies of Starmer had said privately her resignation would be key to allowing the new leader to control the direction of the party. A meeting of the national executive committee will be expected to set a timetable to elect a new general secretary. Potential candidates to succeed Formby are thought to include the Unite political director, Anneliese Midgley, the Unison official Emilie Oldknow and GMB’s director of external relations, Lisa Johnson. Allies of Oldknow and Johnson say it is no coincidence that they have been linked to recent controversies after they were flagged as potential successors to Formby. Oldknow has been accused making inappropriate comments about colleagues in the controversial antisemitism report being investigated by the NEC. Johnson has been closely connected to Tim Roache, the recently resigned GMB general secretary who is under investigation for inappropriate conduct. Her supporters insist she was among the senior figures pushing for his resignation in recent days. Formby’s resignation means that most of left of the party, which until December’s general election controlled all key positions, have been removed. Focus will now fall on whether Karie Murphy, another key Corbyn ally, will remain as a senior member of the party’s leadership. Responding to the decision, Starmer said: “I would like to thank Jennie for her service, and for the personal and professional efforts she has made in advancing the cause she has fought all her life for. “Jennie has led our party’s organisation with commitment and energy through a period of political upheaval, including a snap general election last year. I wish her the very best for the future.” Angela Rayner, Labour’s deputy leader, said: “As a trade unionist and party activist as well as general secretary, Jennie has been a great servant of our movement for many years and blazed a trail as one of our highest achieving women. “She goes with our thanks and gratitude, and I’ve no doubt she will stand squarely behind us as we continue to fight for social justice and the Labour government our country so desperately needs.”