Christian and political leaders in Britain said Monday they were shocked by Pope Benedict XVI's resignation but praised his efforts to build bridges with the largely Protestant nation.
In 2010, Pope Benedict made a historic first state visit to Britain by a pope.
Justin Welby, leader of the world's Anglicans -- who at 57 is 28 years younger than the pope -- said he understood the pontiff's decision "with a heavy heart".
Welby, who is head of the 85-million strong worldwide Anglican communion as the new Archbishop of Canterbury, said Pope Benedict held his office with "great dignity, insight and courage".
His 2010 visit built bridges between the Roman Catholic and Anglican churches and the pontiff held joint prayers with Welby's predecessor Rowan Williams.
The Church of England separated from Rome in 1534.
During the tour, Pope Benedict proved "a witness to the universal scope of the gospel and a messenger of hope at a time when Christian faith is being called into question," said Welby.
In a brief statement, British Prime Minister David Cameron sent his best wishes to the pope following his announcement.
"He has worked tirelessly to strengthen Britain's relations with the Holy See," Cameron said.
"His visit to Britain in 2010 is remembered with great respect and affection. He will be missed as a spiritual leader to millions."
Archbishop Vincent Nichols, the Catholic leader in England and Wales, said he was "shocked and surprised" by the pope's announcement.
"Yet, on reflection, I am sure that many will recognise it to be a decision of great courage and characteristic clarity of mind and action," said Nichols, the Archbishop of Westminster.
"I salute his courage and his decision."
He said Catholics would remember the pontiff's 2010 visit "with joy".
Cardinal Keith O'Brien, the leader of Scotland's Catholics, said he was "shocked and saddened" by the decision.
He urged Catholics in Scotland to pray for the pope "at this time of deterioration in his health as he recognises his incapacity to adequately fulfil the ministry entrusted to him".
O'Brien, the Archbishop of Saint Andrews and Edinburgh, said he also hoped to rely on the prayers of Catholics worldwide as he and his fellow cardinal electors prepare to travel to Rome to choose the next pontiff.
Britain's only other cardinal, Nichols' 80-year-old predecessor Cormac Murphy-O'Connor, told BBC radio: "There's no doubt that age, and I suppose, the struggle of coping with such an extraordinary, onerous task was telling on him.
"I am saddened because I have real affection for Pope Benedict."