Given the task definition and input, reply with output. This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.

Passage: In 1918 Whitehead's academic responsibilities began to seriously expand as he accepted a number of high administrative positions within the University of London system, of which Imperial College London was a member at the time. He was elected Dean of the Faculty of Science at the University of London in late 1918 (a post he held for four years), a member of the University of London's Senate in 1919, and chairman of the Senate's Academic (leadership) Council in 1920, a post which he held until he departed for America in 1924. Whitehead was able to exert his newfound influence to successfully lobby for a new history of science department, help establish a Bachelor of Science degree (previously only Bachelor of Arts degrees had been offered), and make the school more accessible to less wealthy students. Question: Where did Whitehead accept administrative positions?
University of London