The boss of McDonald’s in the U.K. said that the company has received over 400 complaints (some of which included sexual harassment) in a span of four months—sometimes up to two a week—during a Business and Trade Select Committee meeting on Tuesday.

Alistair Macrow, who runs McDonald’s U.K. & Ireland, told MPs that the experiences of some of the fast food chain’s workers were “truly horrific” and “very hard to listen to.”

“These cases… are absolutely horrendous. What I would like to be clear about is that we will tackle them and make sure that we do everything we can to eradicate them from the business,” Macrow said. 

The U.K. chief’s statement comes after an initial investigation by the BBC in July shed light on McDonald’s staff who were routinely harassed, bullied or sexually assaulted at work. The report said that over 100 current and recent workers had allegedly been on the receiving end of such behaviors, following which the company kicked off an investigation. At the time, McDonald’s apologized and said it had “fallen short.”

So far, the company has investigated 157 of the 407 cases of varying nature, Macrow told MPs. Some of those resulted in terminations while others led to disciplinary action. Of the sexual harassment cases, it’s unclear if the workers reported them to the police.      

​​”I am absolutely determined to root out any of these behaviours, identify individuals who are responsible for them and make sure that they are eradicated from our business,” Macrow said. 

McDonald’s has over 170,000 workers across its 1,450 restaurants in the U.K.—89% of those locations are franchises, Macrow said. 

Workers of the 21st Century

Complaints about harassment or forms of abuse had been cropping up for several years, Ian Hodson, the national president at the Bakers, Food and Allied Workers Union, told the Business and Trade Select Committee on Tuesday. He was first alerted of the growing number of claims five years ago, and said the group had spoken to workers across its London stores.

“We need to make sure that this is the opportunity to make employers accountable for protecting people when they go to work,” Hodson said. “In the 21st century in the U.K., it should not happen. When a global corporation, the second biggest employer in the world, which makes billions and billions of pounds, can’t protect their workforce, it’s awful.”

The BBC’s investigation has spurred more McDonald’s workers to pursue legal action through law firm Leigh Day last week. 

McDonald’s declined to comment further beyond Macrow’s remarks from Tuesday, but provided Fortune with his comments in response to BBC’s investigation.

“We started investigations on every single allegation brought to our attention. We also introduced an additional reporting mechanism and reminded employees of every existing channel available to them,” Macrow said in a statement. “I am personally committed to ensuring all cases brought to our attention are investigated quickly and thoroughly.”

Editor’s Note: The headline has been corrected to reflect the nature of the complaints; the article has been updated with comments from McDonald’s.