Social Democratic and Labour Party

The Social Democratic and Labour Party (SDLP; Irish: Páirtí Sóisialta agus Daonlathach an Lucht Oibre) is a social democratic and Irish nationalist political party in Northern Ireland. The SDLP currently has eight members in the Northern Ireland Assembly (MLAs) and two members of Parliament (MPs) in the House of Commons of the United Kingdom.

The SDLP party platform advocates Irish reunification and, pending the unity of all the people of Ireland and while the northern jurisdiction remains part of the United Kingdom, further devolution of powers. It is a sister party of the UK Labour Party, which maintains an electoral pact with the SDLP not to stand candidates in Northern Ireland but to support SDLP candidates instead. MPs from the SDLP sit with Labour MPs on the government benches when Labour is in power, but do not take the Labour whip, though they informally did so historically.

During the Troubles, the SDLP was the most popular Irish nationalist party in Northern Ireland, but since the Provisional IRA ceasefire in 1994, it has lost ground to the republican party Sinn Féin, which in 2001 became the more popular of the two parties for the first time. Established during the Troubles, a significant difference between the two parties was the SDLP's rejection of violence, in contrast to Sinn Féin's then-support for (and organisational ties to) the Provisional IRA and physical force republicanism.