Textbook addendumHere are a couple paragraphs I added to my "Corrections and Updates" page. Your students could add them to their textbooks.
Brexit and May
In the spring of 2016, Prime Minister David Cameron was facing the disintegration of his Parliamentary majority and his government. The demand for Britain's withdrawal from the EU had become irresistible. Even members of the government, when given permission to disagree with the official line, had joined the Brexit (Britain exit) campaign.
Cameron called for a referendum on the issue, assuming that people would not vote to leave the EU. Trade, travel, and occupational opportunities were too great, he assumed.
Boy, was he wrong. Just over half of British voters favored Brexit in the referendum. He resigned.
After a short intra-party campaign, Theresa May was elected leader of the Conservative Party and became the second woman to be Prime Minister of the UK. She had campaigned against Brexit, but promised to carry out the will of the people in ways that didn't hurt the country. During the summer of 2016, she made the rounds of EU prime ministers and presidents (most importantly Germany and France), to discuss how best to end Britain's EU membership while maintaining the trade, travel, and immigration advantages.
Prime Minister May and many observers suggested that no one should expect formal action of the UK's withdrawal from the EU until 2017.