Katherine Ryan has claimed that a very prominent British TV personality is a “perpetrator of sexual assault.” The Canadian comedian, 39, said she previously confronted the unnamed man in front of others but said his alleged unacceptable behavior remains an “open secret” in the industry. Speaking to Louis Theroux on a recent episode of his “Interviews…” series Tuesday, “The Duchess” star elaborated further on this particular high-profile figure, without divulging his name.