Check out this RSC blog post:
Dorothy Crowfoot Hodgkin was a significant mentor for the young Thatcher. Hodgkin was herself a Somerville graduate who had returned to teach chemistry, specialising in the emerging field of x-ray crystallography. Thatcher spent a year in Hodgkin's laboratory, performing research on the structure of gramicidin B - the completion of which occurred about 30 years later.
During her time at Oxford, Thatcher's interest in politics blossomed and in 1946 she became the third woman to be president of the powerful Oxford University Conservative Association. Her strong conservative views were at odds with those of her peers and her mentor (Hodgkin was a liberal and would become the president of the Pugwash Conferences, concerned with reducing the danger of armed conflict and seeking cooperative solutions for global problems). But despite these differences, Hodgkin and Thatcher kept in touch over the years and when Thatcher later became prime minister, she is reported to have installed Hodgkin's portrait at 10 Downing Street.