Earlier this week, I resigned from Keir Starmer’s shadow cabinet, in which I was Labour’s employment rights and protections spokesperson. I am proud to have served, and the decision to resign was the most difficult one of my political life. In my resignation letter to Keir, I set out my reasons. I had been instructed by the leader’s office to argue against raising statutory sick pay at a living wage and against a minimum wage of £15 an hour in a meeting with party members and trade unions. This is something I could not do in good conscience, and I felt it was at odds with the support the party claimed to have for the country’s low-paid workers. It was also at odds with my principles, making my position untenable. In response to my resignation, some of my former shadow cabinet colleagues accused me of deliberately attempting to sabotage the Labour party conference. This is completely untrue. I have been a loyal Labour MP under three successive leaders. In 2015, I supported Andy Burnham in the leadership election, but I respected the decision of the membership and served Jeremy Corbyn as shadow transport secretary until 2019. In the last leadership election, I supported Rebecca Long-Bailey, but I served loyally under Keir for almost two years after his victory. When Keir asked if I would join his team, I told him he would have my loyal support on the basis of the 10 pledges he made during his leadership campaign. I believed that the Keir Starmer who stood on those 10 pledges would be able to unite the party around a programme to deliver social and economic justice, tackle the climate crisis, and in doing so win the support of voters. If Starmer intends to ditch these pledges, which he has signalled this week, I fear this will no longer be possible. Ed Miliband recently argued that public ownership of energy was necessary if we were to address the climate crisis. Only days later, Starmer appeared on television declaring his opposition to nationalisation while sitting in front of an image of his pledge that said the opposite. This behaviour not only undermines good colleagues and prevents Labour from having a credible policy on the climate crisis, it erodes trust. The 10 pledges risk becoming for Keir Starmer what tuition fees were for Nick Clegg. Once you lose people’s trust, there is no coming back. If voters know a politician will mislead his own party members to get elected as leader, why should they believe that promises made in a general election would be kept in government? There is also a serious point about Keir’s mandate. Labour is a democratic party, and Keir was elected as leader on the basis of those pledges. If he had told members that he did not intend to honour them, I do not believe he would have won. If his current position is that the policies can be ditched, he owes it to the party to go back to the membership to seek a new mandate. Starmer’s team have briefed that today’s conference speech will convey the message that “winning is more important than unity”, but one only need to look at the party’s polling and the leader’s approval ratings to recognise that pursuing a path based on breaking promises and needlessly dividing a party is only making a Labour victory less likely. Rather than looking back into the past to Neil Kinnock, the leader and his team should look across the Atlantic to Joe Biden, who recognised that the Democrats’ route to power involved working with the left and the trade union movement. It’s not too late for Keir to learn this lesson and do the same, but I fear time is quickly running out. Andy McDonald is Labour MP for Middlesbrough and former shadow secretary of state for employment rights and protections under Keir Starmer