On 26 June 2016, McCarthy was among dozens of shadow ministers who resigned from Corbyn's team. She argued that "a new leader is needed to take on the challenges ahead". According to McCarthy, in an article for "The Huffington Post": "When the leader's office did venture into Defra territory, they didn't talk to the shadow team". McCarthy does not believe Corbyn is the right Labour leader or a potential prime minister. She supported Owen Smith in the 2016 Labour leadership election.