Another solution might be the dissolution of the United Kingdom leading to some or all of the countries of the United Kingdom (England, Northern Ireland, Scotland, and Wales) becoming independent sovereign states. The Scottish National Party (SNP), which campaigns for Scottish independence, won an outright majority in the Scottish Parliament in the 2011 Scottish election. A referendum was held on 18 September 2014, with voters rejecting independence by 55% to 45%. In Wales, Welsh Nationalist party Plaid Cymru holds Welsh Independence as a long-term aim, while Propel, formerly the Welsh National Party, more aggressively campaigns for independence. In Northern Ireland there are no mainstream political parties calling for an independent Northern Irish state, but parties calling for a united Ireland include Sinn Féin and the Social Democratic and Labour Party (SDLP).