In a highly anticipated testimony to the UK’s public inquiry into the COVID-19 pandemic, former British Prime Minister Boris Johnson struggled to understand much of the science that informed public health decisions during the pandemic, according to his chief scientific advisor Patrick Vallance.

Vallance said that he and others faced repeated problems getting Johnson to understand complex scientific concepts and data, despite his efforts to explain them clearly. “I think I’m right in saying that the prime minister gave up science at 15,” he said. “I think he’d be the first to admit it wasn’t his forte and that he struggled with the concepts and we did need to repeat them — often.”

In extracts from his diary, Vallance revealed that Johnson was “bamboozled” by graphs and data and struggled to grasp basic statistical concepts. He also noted that watching Johnson try to make sense of these issues was often frustrating.

However, Vallance emphasized that Johnson’s struggles were not unique, citing other European leaders who also had difficulty understanding scientific evidence during the early stages of the pandemic. He said: “So I do not think there was necessarily a unique inability to grasp some of these concepts with the prime minister at the time, but it was hard work sometimes to try and make sure that he had understood what a particular graph or piece of data was saying.”

Despite these challenges, Vallance said that he is grateful for having worked with such a dedicated team of scientists during the pandemic response effort. He added: “It is important for policymakers to listen carefully when they are presented with scientific evidence, so they can make informed decisions about public health measures.”