Linked to the Ulster Volunteer Force (UVF) and Red Hand Commando (RHC), for a time it described itself as "the only left of centre unionist party" in Northern Ireland, with its main support base in the loyalist working class communities of Belfast.

[8] The PUP has one elected representative on the Causeway Coast and Glens Borough Council, Russell Watton, the party's current leader.

In 1977, two prominent members of the Northern Ireland Labour Party, David Overend and Jim McDonald, joined.

In 1995, shortly after the Combined Loyalist Military Command announced a ceasefire, former UVF member Billy Hutchinson, who was jailed for the murder of two Catholics in 1974, defined the relationship between the PUP and the UVF: "The relationship is a very strict one in terms of acting as political confidants and providing political analysis for them, but it doesn't go any deeper than that.

[18] [19] Following the signing of the Good Friday Agreement, elections to the new Northern Ireland Assembly were held, which the PUP contested.

In March 2006, the Chairwoman of the PUP, Dawn Purvis, a research associate at the University of Ulster, was appointed as an independent member of the Northern Ireland Policing Board.

In June 2010, Dawn Purvis resigned as leader, and as a member, of the party because of its relationship with the UVF and a recent murder attributed to that group.

[38] During a meeting in Belfast on 29 September 2010, members of the party agreed to maintain its relationship with the Ulster Volunteer Force and the Red Hand Commando.

[46] A month after the elections, Ervine announced his resignation as party leader, and later was replaced by veteran west Belfast activist Billy Hutchinson in October 2011.

[47] Hutchinson succeeded Hugh Smyth on Belfast City Council in January 2014, following the latter's retirement due to ill health.

[50] In Belfast, deputy leader John Kyle was re-elected, this time for the Titanic district, while Hutchinson topped the poll in Court.

[60][61] Following the United Kingdom's withdrawal from the European Union, the PUP have been protesting against the Northern Ireland Protocol, part of the arrangements to prevent a 'hard border' in the Irish Sea.

The party believes that the Protocol inhibits the Principle of consent, leading to Hutchinson saying that the PUP no longer support the Good Friday Agreement in November 2021.

[62][63] Conversely, in an interview on BBC's The View programme, John Kyle stated that the Protocol could have "significant advantages" if "fundamental" changes are made.

[64][65] Kyle subsequently resigned as both deputy leader and a member of the party three weeks later, citing "differing approaches" in regard to the Protocol.

[70] The party polled 2,103 votes (0.3%) overall, and were wiped out in Belfast, with Hutchinson losing out to the Traditional Unionist Voice (TUV).

[74] Former UVF member Billy Giles, who spent 14 years in the Maze Prison for a sectarian killing, was part of the PUP's negotiating team at the Good Friday Agreement in April 1998.