Boris Johnson has failed to deny claims by Rishi Sunak that he is refusing to take calls from his former chancellor. A month after he resigned from cabinet – precipitating Johnson’s ousting from Downing Street – Sunak told a hustings event for the Conservative leadership race on Thursday night that Johnson was refusing to answer or return calls from him. Asked if he would stop ignoring Sunak’s calls, the prime minister told reporters during a visit to North Wales: “That’s one of those Westminster questions that doesn’t change the price of fish.” “There are plenty of things that do change the price of fish, not least the price of energy, but that’s not one of them.” Sunak was asked during a hustings event in Cheltenham whether he had spoken to the prime minister since resigning from government, and replied that he had messaged him and tried calling, but “perhaps not surprisingly” Johnson had not replied. Sunak quit his role in July, within minutes of former health secretary Sajid Javid, with both men citing standards and integrity as the reason. Nadine Dorries, one of Johnson’s closest allies, has suggested Sunak was part of a “coup” that brought down the Tory leader, while a senior No 10 official was quoted in the Financial Times last month as calling Sunak “a treacherous bastard”. Another Johnson supporter in the cabinet told the FT: “Rishi will get everything he deserves for leading the charge in bringing down the prime minister”. Johnson, meanwhile, appeared to be less than enthusiastic about working with Sunak and Liz Truss – the two candidates to succeed him – to devise fresh measures to tackle the cost-of-living crisis. “The cash is not only coming through now, and has started to come through, but will continue to come through over the weeks and months ahead,” the prime minister told reporters. Earlier, the chancellor, Nadhim Zahawi, said he believed the next prime minister could “hit the ground running” to help hard-pressed families. He said his officials in the Treasury were “looking at all the options” for additional help this winter to ensure that either Truss or Sunak had the necessary information to take decisions from 5 September.