In 1876 the UK passed the Cruelty to Animals Act, which directly highlighted the practice of using animals as test subjects, and outlined prosecution for those considered to be unlawfully experimenting. Key points of the Act include the importance for researchers to define the necessity for the use of animals as well as proper care taken to reduce inflicting pain. This was a major step forward for both animal rights and assessment of experimental design. The Cruelty to Animals Act would remain mostly unchanged for over 100 years.