Gregg when explaining his family background, revealed that his father, regarded as a quiet man, had trust in the Royal Ulster Constabulary (RUC) and British Army but joined the loyalist vigilante groups set up around the start of the Troubles ostensibly to protect the Protestant community from attacks by republicans.

His own earliest memory of the Troubles was the Northern Ireland Civil Rights Association marches in Derry, a movement to which Gregg and his family were strongly opposed.

[1] On 14 March 1984, he severely wounded Sinn Féin president Gerry Adams in an attack supposedly ordered as a response to the earlier killings of Ulster Unionist Party politicians Robert Bradford and Edgar Graham.

[7] Sometime after the Combined Loyalist Military Command of 1994 he succeeded Joe English, who had emerged as a leading figure in the Ulster Democratic Party, as so-called brigadier of the South-East Antrim UDA.

[8] Under Gregg the South-East Antrim Brigade were prepared to ignore the terms of the loyalist ceasefire, such as on 25 April 1997 when he dispatched a five-man team to Carrickfergus to set fire to a Catholic church in retaliation for a similar attack on a Protestant church in East Belfast (this earlier attack had actually been organised by dissident loyalists seeking to provoke the UDA into returning to violence).

[13] Along with Jackie McDonald and Billy McFarland, fellow brigadiers on the UDA's Inner Council, Gregg was lacking in enthusiasm for the Belfast Agreement when it appeared in 1998.

[1] Gregg was also characterised as "a bully, a racketeer, and a sectarian bigot who took particular delight in carrying out vicious punishment attacks and randomly targeting Roman Catholics.

[16] Having witnessed demographic shifts in Glengormley and Crumlin, traditionally loyalist majority towns that had come to have nationalist majorities on account of loyalists moving out of Belfast, he determined that the same thing would not happen in Carrickfergus and Larne and so launched a campaign of pipe bomb and arson attacks on Catholic homes there (despite these towns having very small Catholic populations).

The main target proved to be Danny O'Connor, a Social Democratic and Labour Party (SDLP) representative on initially Larne Borough Council and then the Northern Ireland Assembly, whose home and office were attacked at least 12 times by Gregg's men between 2000 and 2002.

[17] Protestant Trevor Lowry (aged 49) was beaten to death in Glengormley by UDA members under Gregg's command on 11 April 2001 after he was mistaken for a Catholic.

A UDA member originally from the Woodvale Road had moved to Rathcoole where he had been beaten up after it emerged that he was a friend of Joe English, the former brigadier who had been exiled from the estate by Gregg for his anti-drugs stance.

[26] Adair ignored the expulsion, erecting "West Belfast UDA - Business as Usual" banners on the Shankill Road, whilst continuing his struggles with the remaining brigadiers, Gregg in particular.

[31] On 1 February 2003, along with another UDA member, Robert "Rab" Carson, Gregg was shot dead on Nelson Street, in the old Sailortown district near the Belfast docks, while travelling in a taxi after returning from Glasgow where he regularly went to Rangers F.C.

Gregg had been a regular visitor to Ibrox Park for a number of years,[11] often in the company of Michael Stone, and had even picked up a conviction for violence at an Old Firm match.

Despite his reputation for gangsterism, Gregg's failed attack on Gerry Adams had afforded him legendary status and, under the direction of Jackie McDonald, the remaining UDA brigadiers concluded that Adair had to be removed.

[34] Gregg was given a paramilitary funeral which was attended by thousands of mourners, including senior UDA members Jackie McDonald, Jim Gray, Sammy Duddy and Michael Stone.

That same night Jackie McDonald's men raided the lower Shankill and ran those members of C Company that had remained loyal to Adair, who was still in prison, out of the city.