Possible Clues:

• Being hardened, a summons is nothing to us
• Hard to contact the Guardian? Ring in!
• Not feeling one can run rings round university
• Cruel and unfeeling
• Insensitive opposition leader follows visit to America
• Unfeeling and cold, completely zero value practically
• Insensitive visit by old American
• Hard to cry over American
• Cold. uncaring
• Hard-hearted relative drops in, overwhelming everyone