Lieutenant Dan Choi, the National Guard soldier who publicly came out live on national television, has been dismissed from duty.

He was dismissed for “homosexual conduct”.

Choi is a campaigner for the repeal of the military gay ban and a founding member of the Knights Out group.

He came out live on US television on the Rachel Maddow Show, where he will reappear tonight to discuss his dismissal.

In a preview of the show, Maddow reads a letter received by Choi from the Army National Guard.

It states: “This is to inform you that sufficient basis exists to initiate action for withdrawal of Federal Recognition in the Army National Guard for moral or professional dereliction.

“Specifically you admitted publicly that you are a homosexual, which constitutes homosexual conduct. Your actions negatively affected the good order and discipline of the New York Army National Guard.”

When being interviewed by Maddow in March, Choi recognised the possibility of him being dismissed but said he and other members of Knights Out felt it was most important to “do the right thing”.

In an interview with PinkNews.co.uk last month, Choi said the gay ban may have undermined the government’s potential to prevent the September 11th bombings.

He said: “On Monday, September 10th 2001, a message was intercepted by the State Department: tomorrow is zero hour.

“Despite its simplicity, nobody was able to translate it. Any of the dozens of linguists already discharged for being gay at the time would have done so easily.”

Around 12,500 servicemembers have been ejected since the Don’t Ask, Don’t Tell policy’s introduction in 1994, including 60 Arabic linguists.