The British scientist known colloquially as “Professor Lockdown,” who pushed Prime Minister Boris Johnson to impose a nationwide lockdown, resigned on Tuesday after he defied social distancing guidelines to have a rendezvous with his married lover in his London home.

Professor Neil Ferguson, who had been praised for his expertise and guidance during the U.K.’s coronavirus outbreak, allowed 38-year-old Antonia Staats—who is married with two children—into his home at the same time he was publicly advising everyone else to adhere to strict guidelines banning couples from seeing each other if they didn’t live together. 

Ferguson, who is the head of the Department of Infectious Disease Epidemiology at Imperial College London, had delivered stark warnings to Downing Street about how many people could die of the coronavirus if the government did not impose restrictions. His renowned work also reportedly informed government responses to coronavirus in the United States, France, and Germany.

“I accept I made an error of judgment and took the wrong course of action,” Ferguson told The Telegraph, which first reported on Ferguson’s ouster. “I have therefore stepped back from my involvement in SAGE [the government’s Scientific Advisory Group for Emergencies]. I deeply regret any undermining of the clear messages around the continued need for social distancing to control this devastating epidemic. The government guidance is unequivocal, and is there to protect all of us.”

The scientist’s lover reportedly made several trips to his home in March and April even though she admitted to her friends that her husband was experiencing symptoms of the coronavirus. Deputy Chief Medical Officer Dr. Jenny Harries and Health Secretary Matt Hancock informed the public one week before the lovers’ first reunion on March 30 that “if the two halves of a couple are currently in separate households, ideally they should stay in those households.” 

According to The Telegraph, Staat and her husband are in an open marriage and Staat did not believe their actions to be hypocritical because she considers the households to be one.

Ferguson has for years modeled the spread of major pathogen outbreaks such as swine flu and Ebola. He tested positive for the coronavirus on March 19 after speaking at a Downing Street press conference two days earlier. He recently completed two weeks of self-quarantine, according to The Telegraph. 

“This virus is probably the one that concerns me the most of everything I’ve worked on,” Ferguson said in a February 14 interview in the early days of the coronavirus outbreak.

The scientist had been on the forefront of the coronavirus fight in the U.K., frequently appearing in interviews to praise “very intensive social distancing” measures. Ferguson heads an Imperial College team that presented a staggering report to the government that projected more than 500,000 deaths in the UK without enforced restrictions. 

“Scientists like him have told us we should not be doing it, so surely in his case it is a case of we have been doing as he says and he has been doing as he wants to,” said British Member of Parliament Iain Duncan Smith. “He has peculiarly breached his own guidelines and for an intelligent man I find that very hard to believe. It risks undermining the government's lockdown message.”