Piers Morgan has called for a rewriting of the Bible to allow for gay marriage.

In a Christmas Eve interview with Rick Warren, Morgan noted that the Bible and the Constitution are “basically inherently flawed” documents.

The 58-year-old Warren is the founder and senior pastor of the Lake Forest, California-based megachurch Saddleback Church – the eighth-largest church in the United States – and the author of the best-selling book The Purpose Driven Life.

Warren appeared on Morgan's CNN program to promote an updated edition of his book.

Morgan argued that the Bible should be amended to reflect changing cultural viewpoints, in particular gay marriage.

“Both the Bible and the Constitution are well-intentioned but they are basically inherently flawed,” Morgan said. “Hence, the need to amend it.”

“Not a chance,” Warren replied. “What I believe is flawed is human opinion, because it constantly changes.”

“But you and I know the Bible is, in many places, a flawed document,” Morgan continued. “My point to you about gay rights for example – it's time for an amendment to the Bible.”

“You should compile a new Bible,” Morgan declared.

“I do not believe the Bible is flawed,” Warren said. “And I willingly admit, willingly admit that I base my worldview on the Bible, which I believe is true, and truth. My definition of truth is if it's new, it's not true. It it was true 1,000 years ago, it'll be true 1,000 years from today.”

“Opinion changes, but truth doesn't,” he added.

“We're going to agree to disagree on that,” Morgan said.