We are not familiar with the superstar judge in Britain. Our adversarial model of justice, in which evidence is gathered by the police and evaluated at trial by a supposedly neutral judge, pretty much precludes it. But in much of Europe, and wherever else in the world the inquisitorial system prevails, it is an independent prosecutor or examining magistrate who directs investigations, seeks out evidence, and interviews all concerned.

It is a role that can, when handled astutely, present the determined, charismatic and above all publicity-savvy jurist with a satisfyingly large stage on which to display their talents – and some do not shy from the opportunity.

One such is Baltasar Garzón, the celebrated – and controversial – Spanish human rights investigator who, as the legal head of anti-secrecy group WikiLeaks, is considering a request for help from US whistleblower Edward Snowden.

Snowden is thought to be trying to get to a country – possibly in Latin America – that would not deport him to the US to face espionage charges. WikiLeaks founder Julian Assange has already been given asylum by Ecuador, and is sheltering in its London embassy. Garzón could act as a go-between.

The former superjudge has denied he already represents Snowden, but confirmed he defends "the right of freedom of expression and freedom of information – the same rights I defend [wherever] the release of information that reveals criminality is met with the persecution of those who expose it".

Garzón, now 57, is probably best known outside Spain for his spectacular coup in securing the arrest of Augusto Pinochet in 1998 in London, where the former Chilean military dictator had travelled for medical treatment. Pinochet was held for 18 months, but eventually released and allowed to return to Chile. Although Garzón ultimately failed to bring the ex-strongman to Spain to face charges of human rights violations for kidnapping and killing Spaniards in Chile, his attempt made headlines around the world.

At home, his crusading reputation was made in the 80s and 90s taking on Spain's toughest corruption and drug rings. He not only went after the violent Basque separatists ETA – but also the government, which was accused of deploying death squads to take out the group's leading members.

Garzón's judicial career in Spain was ended last year when he was banned from the bench for 11 years. The supreme court found him guilty of wiretapping conversations between defence lawyers and clients in a corruption probe involving the prime minister Mariano Rajoy's People's party. He had already been suspended since 2010 after a rightwing group accused him of violating a 1977 amnesty by reopening cases of alleged atrocities committed under the Franco dictatorship between 1936 and 1975.

He now spends little time in Spain, apparently preferring to deploy his talents – both legal and promotional – on an even wider stage.