Catholic cardinals have held a final meeting before shutting themselves into the Sistine Chapel to elect a new pope.

Vatican insiders say an Italian and a Brazilian Cardinal are so far leading contenders for the job.  

The Cardinals  have been debating the challenges that the next pope will face and vetting possible candidates for the post.

The 115 Cardinal electors will take a solemn oath of secrecy on entering conclave.  

Anyone breaching the oath will face excommunication.