How did joan sanderson die?

Joan Sanderson, the British actress known for her work in television and theatre, passed away on May 24, 2009. She died at the age of 90 in a nursing home in London. Her career included notable roles in various TV series, including "Fawlty Towers" and "The Fall and Rise of Reginald Perrin." Sanderson's death marked the end of a significant era in British entertainment.