The magazine on Saturday night disavowed Derbyshire's "nasty and indefensible" posting - which ran on a website unrelated to the National Review - and said it amounted to a "letter of resignation" by the columnist.

"We never would have published it, but the main reason that people noticed it is that it is by a National Review writer," editor Rich Lowry said in a posting on the magazine's website.

"Derb is effectively using our name to get more oxygen for views with which we'd never associate ourselves otherwise. So there has to be a parting of the ways," Lowry said.

Derbyshire's column was written as a response to recent newspaper articles about "the talk" that African American parents have with their children about being black teenagers in a country in which young black men may be considered a potential threat. The articles followed the shooting in Florida of unarmed teenager Trayvon Martin by a neighborhood watch volunteer.