A senior Labour source has indicated that Lord Sugar will not face disciplinary action over his tweets.
The Labour peer took to the social networking site earlier today, to urge people not to back Ken Livingstone in the London mayoral elections.
The source said: "There is a long history of Lord Sugar and Ken Livingstone not being the best of friends".
"Lord Sugar was not recommending people vote for any of Ken's opponents.
"He is a Labour peer but Lord Sugar's views are very much his own."
A full list of the candidates running in the election can be found here.