Union leaders are to meet Keir Starmer for a showdown over the party’s plans to overhaul workers’ rights, with some also expected to express concerns over the defection of Natalie Elphicke. The meeting at the party’s Southwark HQ on Tuesday afternoon comes amid divisions over whether the proposals have been watered down since they were first proposed by Labour’s deputy leader, Angela Rayner. Union general secretaries will convene at lunchtime before the 90-minute meeting with Starmer, Rayner, the party chair, Anneliese Dodds, and the shadow chief secretary to the Treasury, Darren Jones. Unite, the Communication Workers Union and the Fire Brigades Union (FBU) are understood to be raising concerns about the latest draft of the document that includes several changes to the proposals, including the speed and methods of the changes. The party has proposed sweeping overhauls of workers’ rights, including day one protections against unfair dismissal, maternity and sick pay, bans on zero-hours contracts and fire and rehire practices, fair pay agreements and trade union access. But some changes since the rights were first proposed have angered unions, including tweaks to allow workers to stay on zero-hours contracts if they prefer – which they say would be a loophole for exploitation. Other unions have given strong backing to the package, including the TUC, Community and Usdaw. Though the meeting is intended to review the latest draft of the proposals before they become a campaign document for candidates, several general secretaries are expected to express anger at the defection of Elphicke to Labour – highlighting previous anti-trade union comments. The FBU general secretary, Matt Wrack, who became president of the TUC in September, wrote to Starmer over the weekend saying her decision to defect from the Conservatives was particularly concerning because of Labour’s promise to repeal the Strikes (Minimum Service Levels) Act, which effectively bans strike action across parts of the public sector. “Elphicke was a cheerleader for the minimum service levels act and has specifically targeted firefighters in her contributions in parliament,” Wrack wrote. “On Tuesday 12 March this year, she spoke in support of the new anti-union laws by blaming striking firefighters for the deaths of three people during a past national firefighters’ strike. This is a disgraceful attack on firefighters, who protect the public and save lives every day, sometimes at great personal cost,” he wrote. Labour MPs including Rosie Duffield and Jess Phillips had also raised concerns about Elphicke’s defection because she supported her ex-husband and predecessor as MP, Charlie Elphicke, after he was convicted of sexual assault. However, Elphicke was crucial on Monday night to a victory for MPs who campaigned to toughen up plans to bar MPs under investigation for violent or sexual offences to be banned from parliament. MPs from across the house launched an attempt to change a proposed rule that said only those who had been formally charged should be banned. An amendment that said that should be extended to those who had been arrested passed by a single vote, including Elphicke’s. Before this week, parliamentary authorities had no power to ban MPs accused of serious criminal wrongdoing from the estate, though many stay away on agreement with party whips.