Jesselyn Radack, a human rights lawyer representing Edward Snowden, has claimed that she was detained and questioned in a "very hostile" manner on Saturday by London Heathrow Airport's Customs staff.
Radack told civil liberties blog Firedoglake that she was taken to a room to be questioned by a Heathrow Border Force officer who showed very little interest in her passport documents but subjected her to questioning about whistle-blowers Edward Snowden, Bradley Manning and Julian Assange.
The 43-year-old lawyer was formerly an ethics advisor to the United States Department of Justice, who became a whistle-blower herself after disclosing an ethics violation made by the FBI in their interrogation of "American Taliban" suspect John Walker Lindh in 2001.
Radack was on her way to London to meet up with "friends", specifically the Sam Adams Associates, a group of retired CIA officers that promotes ethics and accountability and integrity of government. The group also gives out an annual whistleblower award to people who have made achievements in ethics.
Radack freely disclosed to the border agent that she was going to see members of this group, and when he realised that the meeting would be happening at the Ecuadorian Embassy, he went on to ask her if Julian Assange would be in attendance and to ask her about why she had travelled to Russia twice in three months.
Radack claims that the officer told her that she was questioned because she is on an "inhibited persons list", a term coined by the US Department of Homeland Security. It means the US Transportation Security Administration has officially instructed an airport operator or aircraft operator not to provide the individual with access to an area or with a boarding pass to the destination.
The lawyer says that she kept her composure during the interrogation but was in tears after the ordeal. She said that she felt that the officer had deliberately attempted to intimidate her.
She has also tweeted the American Bar Association.
"Please put out a statement that it is unacceptable for the US (or any) government to monitor, harass, or intimidate attorneys," she writes in her tweet.
Former Tory MP and author Louise Mensch has been responding to Radack's tweets and a row seems to be brewing on Twitter.
Mensch said that she is"proud" that Heathrow Border Force were "doing "their lawful job" by interrogating Radack. She has also insisted that Radack is not actually Snowden's lawyer but merely just a "legal advisor" trying to claim attorney-client privilege.
Both Mensch and Radack's tweets have been retweeted and favourited by their followers at least 10 times.
IBTimes UK has contacted the UK Border Agency and Jesselyn Radack and is currently waiting for a response.
Snowden, a former security contractor for the US government, is now in exile in Russia after he leaked multiple documents relating to NSA surveillance.
Recently, Snowden's documents showed that NSA provided guidance, enabling Australian spies to tap into an American law firm representing Indonesia in a trade dispute with the US.