Complex sentence: The Act was passed during the case of William Palmer due to concerns that he would not be able get a fair trial in his native Staffordshire, making it easy for him to repeal the case, due to local publicity surrounding the case.
Split into simpler sentences: The Act was passed during the case of William Palmer and was based concerns that he would not be able get a fair trial in his native Staffordshire. They would make it easy for him to repeal the case by local publicity surrounding the case.