[1][2] In early 1972, Georgiou and three other paratroopers, Privates Cyril Verbeck, Stephen Peter Kirby, and Michael Wainhouse, carried out an armed robbery at a Post Office.

An acquaintance, Nick Hall, another dishonourably discharged airborne veteran, took the initiative of putting out an advertisement soliciting mercenary employment for four able-bodied young men.

The men received a prompt reply from "Dr." Donald Belford, a former British Army medic who had volunteered for a humanitarian aid group in Africa some years before.

Georgiou was now using the nom de guerre "Colonel Tony Cullen"[4] – the surname of a former army friend and not, as mistakenly alleged by some journalists,[citation needed] inspired by the TV espionage series Callan.

Within 48 hours of his arrival in Angola, Georgiou had already led his men in disarming and massacring a group of FNLA fighters (his supposed allies), whom he killed just for the "fun" of it all.

This, combined with the foreign origin of most of the core leadership, (Georgiou, Christodoulou and the Portuguese), created a deep gulf between the officers and the British other ranks – to say nothing of the native Angolans recruited as infantry and support troops.

The first contingent of mercenaries was mostly made up of professional soldiers, selected by a British private military company (PMC), Security Advisory Services (SAS), run by John Banks, Chris Dempster, and Dave Tomkins.

Georgiou became increasingly paranoid and belligerent toward his own men, murdering African soldiers and creating a climate of fear even among the British mercenaries, none of which aided the morale of the FNLA forces or their ability to wage war successfully against the MPLA.

The British journalist Patrick Brogan called Georgiou a "psychopathic killer" who executed 14 of his fellow mercenaries for cowardice, and was extremely brutal to black people.

However, given his limited resources and the fact that many of his men – European and native alike – were untrained, increasingly demoralised amateurs, Georgiou's campaign was ultimately a failure.

In addition he was charged with involvement in the massacre of fourteen fellow mercenaries at Maquela do Zombo in northern Angola, as well as with the murder and torture of enemy soldiers and civilians in the town of São Salvador.

[7] The killings at Maquela occurred after some mercenary recruits had mistakenly opened fire on their colleagues and, fearing retribution by Georgiou and the MPLA, had subsequently fled towards Zaire, taking all the unit's supplies.

President Agostinho Neto rejected pleas for mercy from Queen Elizabeth II on behalf of Georgiou and three other condemned British mercenaries.

Georgiou's body was repatriated to England, and he was buried secretly in a cemetery in north London in accordance with the rites of the Greek Orthodox Church.