Mr Johnson told radio station LBC 97.3 that Ms Thatcher should have been given a quiet warning about her language.
He said: "If someone says something a bit offensive and you are the producer of the show and everybody else has taken umbrage and feels uncomfortable, then you take that person on one side.
"You say 'Listen, you've got to understand we've all got to work together and you've got to watch what you say and you've got to be sensitive'."
'Nasty attitude'
Pop star Will Young has accused the BBC of panicking in its decision to axe Thatcher.
Speaking on the BBC's Question Time, the 30-year-old politics graduate said: "I don't think it's the right decision.
"I feel sorry for the BBC because there's a culture of timidity and they really don't know which way to turn."
"Carol Thatcher used the word in a private conversation, they panicked."
But Communities Secretary Hazel Blears will voice her support for the BBC's decision in a speech to Labour Party activists in Manchester tomorrow.
She is due to say: "It is right that the BBC took the action they did - they deserve credit for protecting their employees from offensive racist language.
"Of course 'golliwog' is an offensive, racist word when directed at a black person. It is a nasty word, and belies a nasty attitude."
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