It has been reported Mr Brown suggested a visit could coincide with the beatification of Cardinal John Henry Newman - a famous British convert to Catholicism, who died in 1890 - expected within the next two years.

BBC: Pope is 'considering' visit to UK

Pope Francis' success is also likely to hinge on his choice of bishops, the local administrators and pastors who interact with the Curia and carry out directives in Catholicism's' far-flung dioceses, said Cardinal Murphy-O'Connor.

WSJ: Bid to Remake Church Will Focus on Vatican Administration

Cardinal Ratzinger was named the prefect of the Congregation for the Doctrine of the Faith, making him Catholicism's theological watchdog in charge of monitoring and disciplining clergy who advocated teachings that ran contrary to Vatican positions.

WSJ: Pope Defended Church Teachings