Labour is refusing to promise to repeal all of the Conservatives’ proposed anti-strike laws, despite calling them “unworkable” and “grandstanding”. Neither Keir Starmer, the Labour leader, nor Rachel Reeves, the shadow chancellor, would commit on Thursday to reversing the proposals, which include strict curbs on when public sector workers can strike, if Labour wins the next election. Rishi Sunak this week promised “tough new laws” to limit strikes, as Border Force guards became the latest group to announce they plan to walk out in the coming weeks. The government is already working on legislation to force transport workers to provide set minimum levels of service, while Sunak has refused to rule out completely banning emergency service workers from striking. Starmer called the proposal to ban emergency strikers “wrong” but would not commit to scrapping it if it became law. Reeves said that committing to repeal was “jumping the gun a little bit”. “The Conservatives U-turn every day of the week and I would expect to have several more before we get to the next election,” she said. They have previously promised to repeal the minimum service legislation. Starmer and Reeves were speaking to an audience of business leaders at Canary Wharf as part of the party’s “prawn cocktail offensive 2.0”, which is seeking to repeat Tony Blair’s success in persuading business leaders to back Labour. The event on Thursday included speeches by Amanda Blanc, the chief executive of Aviva, and Ian Stuart, the chief executive of HSBC UK. Jim O’Neill, the former Goldman Sachs banker and Treasury minister under David Cameron, also spoke, having helped formulate the party’s policies towards startups. Starmer told the conference: “Labour is back in business … We have more business engagement in the last two years than the Labour party has had in well over a decade.” Labour’s promise to the business community includes scrapping business rates and more public investment in sectors like the green economy. Reeves also announced a range of proposed policies designed to help startups and small businesses, including greater independence for the British Business Bank to invest in fast-growing companies. “The French are starting to eat our lunch when it comes to investing in startups,” she said. “I want us to get a slice of that action.” Starmer said meanwhile the party would not levy windfall taxes on the financial services industry as it is promising to do on the energy industry. Asked to guarantee this would not happen, he replied: “Yes. We set out our fiscal rules very early.” The charm offensive appears to be winning supporters among the business community. Stuart told the event on Thursday: “I’m delighted to be supporting today’s event, which represents another reminder of the commitment Labour has made under Sir Keir and Rachel, to deeper engage with business.” A corporate lobbyist told the Guardian the party looked like “grownups” compared with the government. But Labour is in a more awkward position when it comes to its position on the strike action, which threatens to bring much of the country to a standstill over the winter, not least because it is still heavily reliant on union funding. Figures released this week showed that the party received £1.6m in trade union donations between July and September this year, compared with £1.5m from individual donors. Starmer expressed sympathy with those going on strike, saying: “They are facing a very real cost of living crisis. They’re struggling to pay their bills.” But neither he nor Reeves would say whether they wanted to see them being paid more. Reeves said: “I’ve always said Labour will not pluck numbers out of the air and everything in our manifesto will be fully costed and fully funded.”