An ancient Coptic papyrus fragment which referred to Jesus' "wife" is almost certainly fake, the Harvard professor who discovered it has admitted.

'The Gospel of Jesus' Wife' was publicised in 2012 by Dr Karen King, and she has since defended its authenticity against claims that it was forged.

On June 16, however, King said: "It tips the balance towards forgery".

Her admission followed an investigation published by The Atlantic into the fragment's owner, Walter Fritz.

"It appears now that all the material Fritz gave to me concerning the provenance of the papyrus... were fabrications," King told the Boston Globe.

She said that an "utterly definitive" conclusion that the papyrus was faked could not be made until scientific evidence proved otherwise, but conceded to The Atlantic that current evidence "presses in the direction of forgery".

Fritz has denied that he forged the document.

The business card-sized fragment contains a line that reads: "Jesus said to them, 'My wife...'" and "she will be able to be my disciple".

It also makes reference to "Mary", which has been interpreted as referring to Mary Magdalene.

Carbon-dating tests suggested that the papyrus dates back to around 741 AD, and the ink could also be ancient.

However, numerous scholars have contested its authenticity over the past four years.

Cambridge University's New Testament Studies journal last year devoted an edition to the controversy, with contributions from leading scholars providing damning critiques of the fragment.

One of them, Dr Christian Askeland, found during an intensive study of the text that it was made with the same ink, the same writing implement and showed the same handwriting as a fragment from John's Gospel, written in the Lycopolitan Coptic dialect – which itself was copied almost exactly from a 1924 book on a Lycopolitan John's Gospel found in a jar at Qau el-Kebir the previous year. Askeland argued that since both were written by the same person and that one is definitely a forgery, so is the other.