In July 1989, Thatcher removed Geoffrey Howe as foreign secretary after he and Lawson had forced her to agree to a plan for Britain to join the European Exchange Rate Mechanism (ERM). Britain joined the ERM in October 1990. On 1 November 1990, Howe, by then the last remaining member of Thatcher's original 1979 cabinet, resigned from his position as deputy prime minister, ostensibly over her open hostility to moves towards European Monetary Union. In his resignation speech on 13 November, which was instrumental in Thatcher's downfall, Howe attacked Thatcher's openly dismissive attitude to the government's proposal for a new European currency competing against existing currencies (a "hard ECU"):