The Archbishop of Canterbury has expressed that he is praying for the Pope, admist fears he may resign.

The Pope has recently had to have surgery on his knee resulting in him having to postpone his Apostolic Journey to the Democratic Republic of Congo and to South Sudan.

Rt Rev Justin Welby was due to meet him in South Sudan on the tour and took to Twitter to express his condolences.

Rt Rev Justin Welby said: "I am praying for my dear brother @Pontifex and share his regret that our visit to South Sudan with @ChurchModerator is postponed.

"I continue to pray for the people of South Sudan in their challenges and hopes for peace, and look forward to this historic visit at a later date."

There is said to be feverish speculation about whether the 85-year-old Pope might be preparing to follow the precedent set by his predecessor Benedict XVI, who surprised the world when he resigned in 2013.

The talk grew after he announced he would travel to the Abruzzo town of L’Aquila in late August to attend a feast that was initiated by a 13th-century pope who himself resigned after just five months in the job.

However some Vatican insiders say he will not step down.

Francis, who appeared in public using a wheelchair for the first time in early May, has cancelled several engagements since having a minor operation to treat knee pain.