Upon TMNT 's first arrival in the United Kingdom and Ireland the name was changed to `` Teenage Mutant Hero Turtles '' ( or TMHT , for short ) , since local censorship policies deemed the word ninja to have excessively violent connotations for a children 's program ( in Ireland , however , the first season aired as `` Teenage Mutant Ninja Turtles '' before changing to `` Teenage Mutant Hero Turtles '' ) .
The Teenage Mutant Ninja Turtles ( TMNT ) or in the UK earlier known as the Teenage Mutant Hero Turtles ( TMHT ) are a group of fictional characters .