He became Prime Minister following the resignation of Margaret Thatcher, and in 1992 he was returned for a further term. His premiership saw the joint Downing Street Declaration of the UK and Irish governments, which initiated a new peace process in Northern Ireland, and the negotiations leading to the signing of the Maastricht Treaty. Major survived a leadership challenge in 1995, but was faced with divisions within the Conservative Party over the degree to which Britain should integrate with Europe. He led the Conservatives to a dramatic defeat in the 1997 election.