The dispute dates to 2001, when Hyperion recorded a CD of the music of French Baroque composer Michel-Richard de Lalande. The recording, which featured the Ex Cathedra choir, made use of a performing edition of Lalande's music prepared by Sawkins.

In an apparently unprecedented move, Sawkins demanded royalties from the label, claiming that the intense research involved in creating the edition entitled him to the same rights as the author of a work. Hyperion agreed to pay a "hire fee" for the use of Sawkins' version, but refused to pay royalties, arguing that "an edition of existing musical work that is a faithful reproduction of Lalande's music cannot itself be an original music work."

After attempts at a negotiated settlement, Sawkins took Hyperion to court. After a six-day trial in May 2004, a judge ruled that all but one of the works on the CD involved a large enough contribution on Sawkins part to entitle him to royalties.

"I am not persuaded that one can reject a claim to copyright in a new musical work simply because the editorial composer has made no significant changes to the notes," Justice Patten wrote. "The question to ask in any case is whether the new work is sufficiently original in terms of the skill and labour used to produce it."

In Hyperion's appeal, the company argued that the judge misunderstood the degree of Sawkins' contribution to the work, and ignored a previous case in which a court ruled against the editor of a literary work.

Sawkins and Hyperion agree that a victory for Sawkins would force a major change in the practices of records companies.

"I am delighted with the outcome, which should fire a shot across the bows of record companies," Sawkins said in a statement last year. "Too often in the past editors have been prepared to sacrifice their rights in order to see their edition of a long-forgotten masterpiece recorded."

A statement recently issued by Hyperion said, "If the...decision is allowed to stand, the consequences for the recording industry will be far-reaching. Publishers will be able to exert copyright on a whole swathe of editions which are currently in the public domain."

"Should Hyperion lose," the statement added," the financial liability will be in the region of one million pounds. This is a potentially crippling sum for a company of Hyperion's size."