Labour has attracted a surge of interest from big business at its conference in Liverpool with the biggest attendance of companies since 2010, including a firm owned by a major Tory donor. Keir Starmer and Rachel Reeves were among the senior politicians to speak at a packed reception of more than 600 business leaders, executives and international guests on Monday night. Labour sources said there had been a significant increase in business interest in its conference as the party continued to perform well in the polls, with bookmakers putting Starmer odds-on to win the next election. One of the companies to showcase its wares at the conference was Wrightbus, owned by the Tory donor Jo Bamford, with the firm exhibiting a hydrogen bus at both Labour and Conservative events this year. Others with stalls in the main exhibition hall included Sainsbury’s, Google, Lloyds Banking, and the energy company E.ON, while people were queueing out of the door to get into a business reception. Labour’s business forum – where companies pay for access to events attended by shadow ministers and officials – was sold out in July with more than 90 companies in attendance, and ended up oversubscribed by two to one. Starmer, Reeves, the shadow chancellor; Jonathan Reynolds, the shadow business secretary; and David Lammy, the shadow foreign secretary, all spoke at the reception for businesses, ambassadors and international visitors, which was sponsored by Bloomberg. A senior Labour source said there had been a huge increase in engagement from businesses this year. “They are genuinely encouraged to see a sensible, functioning opposition party. The vast majority aren’t party political – there is just a sense of relief that there are some grownups in the room,” the source said. “They have been welcoming engagement from Labour that they didn’t have previously for quite a long time. The more the polls show we are ahead, the more they are reaching out to us.” Starmer and Reeves have been doing breakfasts, dinners and other events with chairs, chief executives and trade bodies over the past year as part of a concerted effort to reach out to businesses. They also plan to hold a business conference later in the year, and have placed policies such as overhauling business rates, promoting growth, investing billions in green energy and fiscal responsibility at the heart of their offer. One City public affairs professional who had recently been close to the Tories said their company had come to Labour conference for the “first time in forever” because it was “time to listen to what Labour has to say”. The number of parties held by lobbying firms also appears to have swelled. Party donations are increasingly coming from businesses as well as traditional trade union donors, with the help of Lord Levy, Tony Blair’s former fundraiser. Trevor Chinn, a financier and businessman, and Sir Victor Blank, the former chairman of Lloyds Banking Group, who both donated during the New Labour and Miliband eras, have returned to giving money since Starmer became leader. The party also this year accepted £250,000 from Fran Perrin, 43, the daughter of Lord Sainsbury of Turville, who is part of the supermarket dynasty. While the Labour leadership believes business interest in its conference is a good sign, not everyone was pleased to see an increased corporate presence at the four-day event in Liverpool. A Momentum spokesperson said it did not show Labour on the side of workers. “With the Tories siphoning off money to the richest at the expense of the rest of us while attacking trade union rights, Labour needs to show it’s on the side of working people. “It’s both disappointing and self-defeating, then, that Labour’s leadership has banned picket-line visits to workers fighting for their livelihoods in a cost of living crisis while instead hobnobbing inside conference with the big business elite. Labour was founded to champion the interests of workers, not business – that must be our guiding mission.” A Labour source said: “We have a grown-up relationship with business. That doesn’t necessarily mean we’ll always agree, but the important thing is we’re doing the work to understand their perspective.” The Tories and Labour have been criticised in the past for charging businesses to attend their conferences, where they gain access to influential politicians.