In his various teaching posts since then, including twenty years at the University of Glasgow, Sirc was a leading expert on socialist economics and communist regimes.

After the fall of the communist regime in Slovenia, Sirc was active in Slovenian public life, writing articles, giving interviews, and commenting on political developments and economic issues.

Sirc supported a unified and democratic Yugoslavia and, although he admitted this solution was not feasible at the time, he refused to uphold the idea of an independent Slovenia until the outbreak of the Ten-Day War.

In fact, as subsequent polls showed, the great majority of the Liberal Democratic Party's voters voted for Milan Kučan in the presidential elections.

In the late 1990s, he collaborated with the writer Drago Jančar and historians Vasko Simoniti and Alenka Puhar in staging an influential exhibition on human rights violations in communist Slovenia called Temna stran meseca (The Dark Side of the Moon).