On succeeding Thatcher, the Major government had to decide its position on the negotiations on European Economic and Monetary Union (EMU) which would lead to the Maastricht Treaty. It had been Thatcher's opposition to EMU which triggered the end of her premiership. Like Thatcher, Lamont was a long-standing opponent of EMU and the European single currency. In his memoirs, Lamont wrote that he was "horrified" when Ted Heath in 1972 announced Britain that it was accepting the Werner Plan for monetary union. Newly appointed as Chancellor, Lamont therefore supported John Major's idea of Britain negotiating an opt-out from the single currency. Negotiations on the economic aspects of the proposed treaty began in earnest at the end of 1990 with monthly meetings of European finance ministers. At an Intergovernmental Conference held in Rome on 15 December 1990, Lamont declared, "I remain unconvinced that the potential benefits of a single currency are as great as its supporters allege."