According to The Times, the score disappeared during 1994 from Elgar's Birthplace Museum in Worcestershire. It had been bequeathed by the composer's daughter, Carice, to the Elgar Foundation.
The manuscript then appeared on an episode of the BBC’s Antiques Roadshow filmed last year at Cardiff Castle.
The newspaper said that after the £80,000-100,000 valuation on the programme, the present owner had asked Christie’s to sell the manuscript.
The BBC programme was broadcast on Sunday July 8, and on July 9 an article in The Times reported David Mellor, the chairman of the Elgar Foundation, is threatening legal action if the manuscript is not returned.
"I don't know how this unique manuscript left the possession of the Elgar Foundation or got into this lady's hands," he told The Times. "But one thing is certain. She has no proprietary right to it and we have already warned Christie's that this property cannot be sold by them because the person who is offering it is not the legitimate owner. We hope she will admit this without the need for legal action but if she doesn't there will of course be legal action."
No planned auction
Christie's confirmed to ATG that the score was not being offered in "any forthcoming sale".
During the broadcast of the Antiques Roadshow, manuscript expert Justin Croft told the current owner that the "rough draft of the score" had belonged to August Johannes Jaeger, one of Elgar's closest friends.
Jaeger was the inspiration for Nimrod, the ninth and perhaps most famous movement of the Enigma Variations. Croft said that the draft allowed us to "look right into Elgar's head".
The owner of the manuscript was not identified during the broadcast but The Times reported she is Jude Hooke and the manuscript had belonged to her late husband Timothy Hooke who had worked at Harrison Clark Rickerbys, a firm of solicitors, at the same time as Sam Driver White, the former vice-chairman of the Elgar Foundation. Driver White died in February 2017. Hooke died in 2011.