4.24pm GMT

Alex Fenton-Thomas profiles the two other candidates that bookies are now predicting might replace Benedict.

Cardinal Francis Arinze

Converted from traditional animist beliefs at the age of nine, the Igbo Nigerian Cardinal Francis Arinze has been touted as papabile since before Pope John Paul II and was a leading candidate to be elected in 2005.

He made his name during the Nigeria-Biafra war when, as archbishop of Onitsha, he organised the distribution of food and medical supplies to the poor in a region torn apart by the conflict. He was made a cardinal in 1985 and is known for his tolerance of elements of traditional worship in Catholic mass.

Cardinal Marc Ouellet

Marc Ouellet, a French-Canadian, has also been linked with the papacy in the past, especially since being appointed the head of the Congregation of Bishops, which appoints bishops throughout the world. Born in 1944 in rural Quebec, he was appointed archbishop of Quebec in 2002 and made cardinal a year later. He attracted controversy in 2010 when he addressed an anti-abortion conference in Quebec City, saying that terminating a pregnancy was a "moral crime".

And west Africa correspondent Afua Hirsch adds this on Cardinal Peter Turkson:

Cardinal Peter Turkson

Peter Turkson, 64, was born on 11 October 1948 in Nsuta-Wassaw, a mining hub in Ghana’s western region, to a Methodist mother and a Catholic father. He studied and taught abroad in New York and Rome, before being ordained to the priesthood in 1975 and appointed archbishop of Cape Coast – the former colonial capital of Ghana and a key diocese – in 1992.

As archbishop Turkson was known for his human touch, colleagues said. “We love him,” said Archbishop Gabriel Charles Palmer-Buckle, metropolitan archbishop of Ghanaian capital Accra, who was made archbishop in Ghana at the same time as Cardinal Turkson and has known him since school. “For Ghanaians he was our first cardinal, and to be made cardinal in his 50s was a big feather in our cap."

Turkson’s popularity in west Africa has been boosted by his regular TV appearances, particularly a weekly broadcast on state television channel Ghana TV, Catholic Digest. He has maintained strong ties with his native country in addition to his duties in the Vatican.

Turkson’s time in the role has not been without controversy, however. He sparked an outcry last year when he screened a YouTube film at an international meeting of bishops featuring alarmist predictions at the rise of Islam in Europe.

The clip, Muslim Demographics, features claims such as: “In just 39 years France will be an Islamic republic.”

Colleagues in Ghana voiced approval towards Cardinal Turkson’s stance on social matters, but confirmed that he would be unlikely to take the church in a radical direction on contentious issues such as abortion and contraception.

In the past Turkson has not ruled out the use of condoms but advocated abstinence and fidelity, and treatment for HIV infected people above spending on and promoting the use of contraception.