A UK court has ordered Eric Watson ordered to pay £25,259,986.49 (NZ$49.4 million) plus costs in a court case brought by Sir Owen Glenn's Kea Investments.

Glenn, who has been battling cancer since 2012, won a legal victory over Watson In July.

The High Court in England and Wales ruled Watson had engaged in "deliberate deception" when the pair set up a joint venture.

Glenn had seen a large chunk of his fortune tied up in the arrangement, and had spent the past five years fighting in English, California and British Virgin Islands courts to extricate himself and his £129 million ($250m).

He's was seeking compensation for legal costs and the opportunity cost of having the money frozen — although that won't be decided until September and he can't comment on how much he is seeking.

Watson disputes the judgment. He has said he has a new legal team and will look to appeal the decision.

"This is by no means over and I look forward to success in the course of time," Watson said in August.