Porter is sought in connection with a robbery at Andrew Michaels Jewellers in Newark on 6 January 2016.
Matthew Porter, 35, from Boston, Lincs, was arrested on suspicion of conspiracy to commit robbery on January 11, 2016 and released on police bail.
However, Porter has failed to answer bail and is now wanted.
It is believed Porter may be in the Boston/Lincolnshire area.
Anyone with information on Porter’s whereabouts is urged to call Nottinghamshire Police on 999 or Crimestoppers anonymously on 0800 555 111.