David Cameron said originally that he would linger on as Prime Minister, but not take any action to actually Brexit and leave it to the next Prime Minister. Forces in Europe were very loud that this was unacceptable. They can live with Brexit or they can live with no Brexit, but they can’t live with indecision.
Cameron will resign Wednesday and be replaced by Theresa May, who is being framed as similar to Margaret Thatcher. A straight forward, hard as nails Conservative. She currently says “Brexit means Brexit”