The pontiff, who has largely disregarded protocol since his election earlier this month, urged his fellow clerics before the ceremony to prioritise the poor.

“We need to go out to the outskirts where there is suffering, bloodshed, blindness that longs for sight, and prisoners in thrall to many evil masters,” he said at a mass in St Peter’s Basilica.

“It is not in soul-searching or constant introspection that we encounter the Lord.”

Francis, the first leader of the Catholic Church from Latin America, led a mass with a mixed group of young offenders at the Casal del Marmo prison outside of Rome.

The 76-year-old, who was archbishop of Buenos Aires until chosen as pope, has already made a name for himself as a champion of the disadvantaged. In his homeland of Argentina he was known for his strong social advocacy, working in slums and shunning the lavish lifestyle adopted by some senior clerics. He lived in a small flat near the cathedral, flew to the Rome conclave in economy class, and chose to travel with his fellow cardinals by minibus rather than in the papal limousine.

Cardinal Jorge Mario Bergoglio - as Pope Francis was previously known - had already washed and kissed the feet of women in past ceremonies in Argentinian jails, hospitals and old people's homes, including pregnant mothers and AIDS patients.

Before performing the traditional feet washing, in his first general audience on Wednesday, Francis called on the world’s 1.2 billion Catholics to reach out to “lost sheep” over the coming days.

“Holy Week challenges us to step outside ourselves so as to attend to the needs of others: those who long for a sympathetic ear, those in need of comfort or help,” Francis told thousands of faithful gathered in St Peter’s Square.

On Good Friday, Francis will recite the Passion of Christ – the story of the last hours of Jesus’s life – in St Peter’s Basilica, before presiding over the Via Crucis ceremony by the Colosseum, where thousands of Christians are believed to have been martyred in Roman times.

While last year his predecessor, 85-year-old Pope Benedict, presided over celebrations from under a canopy next to the Colosseum, Francis is expected to take part in the procession and even carry the wooden cross on his shoulder for part of the way.

On Saturday, the pontiff will take part in an evening Easter vigil in St Peter’s Basilica, and on Easter Sunday the he will celebrate Easter mass in front of tens of thousands of pilgrims in St Peter’s Square and then pronounce the traditional “Urbi et Orbi” blessing to Rome and the world.

Also on Thursday, the Pope made his first appointment of a bishop, naming Mario Poli, 66, to succeed him as archbishop of Buenos Aires and the top churchman in Argentina.

Francis also put his first people on the path to sainthood, unveiling a list of 63 people including victims of the Spanish Civil War, Nazism and Communism. The largest number are considered martyrs of faith killed during the 1931-45 conflict in Spain.