BBC Religious Affairs Correspondent Emily Buchanan: Several bishops now believe that they should marry

The Bishop of Durham, the Right Reverend Michael Turnbull, said it would be possible for Charles to remarry and still maintain the moral authority to become head of the Church of England on his accession to the throne.

He said that marriage was "more desirable morally" than the couple's current situation of "flux".

When Charles becomes King, he will also adopt the role of Supreme Governor of the Church - a position that would, theoretically at least, be impossible should he choose to remarry.

Michael Turnbull: "As a widower, Charles can remarry"

Debate began even before Diana, Princess of Wales, was killed in a car crash in Paris last year.

In early 1997, the Archbishop of Canterbury, Dr George Carey, controversially warned that Charles's remarriage would throw the church into crisis.

But a recent reports have indicated that opposition, voiced by more than half of England's bishops in a poll two years ago, has begun to soften.

The BBC's Doug Morris: "It can be argued on ethical grounds"

Responding to these reports, the Bishop of Durham said: "Morally and ethically it would be more desirable for them to marry than for the situation to remain as it is."

Camilla Parker Bowles: Could become Charles's queen

The prince and Mrs Parker Bowles have made several low-key appearances together in public in recent months, but there has been no suggestion from Buckingham Palace that their relationship will be placed on a more formal footing.

The Bishop of Durham's comments follow an encouraging message from the Bishop of Oxford, the Rt Rev Richard Harries, chair of the Church of England's board of social responsibility.

Speaking to the BBC, Bishop Harries said: "The fact they can get some support and mutual encouragement from one another, and clearly have a very deep relationship, I think deserves understanding and compassion."

However, he added that no pressure should be put on the couple.