Iron Lady Thatcher's US alias was 'Mrs Stone'

Former British prime minister Margaret Thatcher had the pseudonym "Mrs Stone" when visiting the US in 2002, a declassified Department of State file shows.

File image of the late former British Prime Minister Margaret Thatcher in 2002.

So-called "Iron Lady" Margaret Thatcher had the pseudonym "Mrs Stone" when travelling to the United States, newly-released official documents show.

A declassified US Department of State file shows the former British prime minister travelled under the name in 2002 when flying into Miami.

Thatcher remained popular in the US long after her resignation as prime minister in 1990.

Thatcher's pseudonym was disclosed after a Freedom of Information request by Shawn Musgrave, projects editor at website muckrock.com.

The document released on the website shows a message from the US embassy in London to the US Secretary of State, listed under the subject "protective security - travel of Margaret Thatcher to the US".

It states: "Margaret Thatcher will travel to the US on 12/4/02 arriving at Miami International Airport on Flight BA 2013 1815 under the name of Mrs Stone. She will be accompanied by two armed police officers."