He and his ex-wife, former actress Pamelyn Ferdin, were banned from entering the United Kingdom in 2004, on the grounds that their presence, according to the Home Secretary, "would not be conducive to the public good.

He acknowledges his medical background provides a "certain amount of credibility" to the movement and has used it to advocate against the use of animals in scientific experimentation.

In his summation, Dr. Vlasak said: Here in the U.S., there are thousands of physicians like myself who realize there is no need to kill animals in order to help humans, the vast majority of whom get sick and die because of preventable lifestyle variables such as diet, smoking, drugs and environmental toxins.

[7]Vlasak has been active in opposing the seal hunt in Canada, which occurs every year, mostly in March and April.

He was punched in the face by sealers during the 2005 hunt on Prince Edward Island, which he attended on behalf of the Sea Shepherd Conversation Society.

He was sentenced to 22 days in prison, which he voluntarily re-entered Canada to serve in a Prince Edward Island jail in 2006 in protest of that year's seal hunt.

[11]Following the August 2, 2008, firebombing of a house belonging to University of California Santa Cruz animal researchers, Vlasak was quoted as saying "This guy knows what he is doing.

Newsweek reported "The ALF Press Office's Vlasak says that the plan will be ineffective, in part because it circumscribes the actions of only five above-ground protesters.

"[13] The controversy continued in July 2004 when Jamie Doward of The Observer wrote that Vlasak had told him during an interview: "I think violence is part of the struggle against oppression.

[15]He told the BBC's Today program: "I am personally not advocating, condoning or recommending that anybody be killed.

"[17] As a result of the Observer article, the British government announced in August 2004 that Vlasak and his wife were banned from the UK.

Steven Best, professor of philosophy at the University of Texas, El Paso, and a former press officer, was banned in 2005 to prevent him from addressing an animal rights conference there.