Splits over Europe and the introduction of the poll tax led to Thatcher's resignation in November 1990, following a leadership contest that, after the first round of counting, indicated a lack of support among Tory backbenchers
Gordon Brown still had few MPS willing to energetically defend him in the press
Theresa May accepted that she would step down as prime minister after the Brexit process was completed, a price she had to pay for surviving a motion of no confidence as party leader in December 2018
