Lord Irvine, sitting in the House of Lords with Lords Hoffman, Nicholls of Birkenhead, Clyde and Millet, dismissed her right to sue the British Athletics Federation (BAF) for adopting the drug test results of an unaccredited Portuguese laboratory in its decision to ban her from competitive athletics.
However, Ms Modahl, the 800-metres winner in the 1990 Commonwealth Games, is still committed to bringing a pounds 1m damages claim against the BAF on other grounds. She claims that there was bias during disciplinary proceedings brought against her which resulted in her being banned from international sport for nearly a year before she was cleared on appeal.
Ms Modahl, 33, is seeking to recover the pounds 480,000 she spent on legal and medical costs in challenging the four-year drugs ban imposed by the BAF after urine tests in Lisbon in 1994 allegedly showed a high level of testosterone in her body.
The ban was eventually lifted by an appeal tribunal and the International Amateur Athletic Federation (Iaaf) after doubts were cast on the accuracy of the tests.
She is also seeking a similar figure in punitive damages over the way her case was handled by the BAF.
Her lawyers argued that the Lisbon laboratory lost its accredited status by moving to different premises without notifying the Iaaf or the International Olympic Committee. Strict accreditation was a "fundamental safeguard" for an athlete charged with doping.
The BAF denied that the move had any such effect, and yesterday Lord Hoffmann said he would find it "remarkable" if it did. But the question to be decided was whether any breach of international guidelines by the Portuguese Athletic Federation entitled Modahl to sue the BAF.
It was not alleged that the BAF knew, or ought to have known, that the laboratory was not accredited, said Lord Hoffmann.
It would be inconsistent with Iaaf procedures to imply that national federations should not initiate disciplinary proceedings simply because the laboratory had done something to negate its accredited status. To impose on the BAF a potentially large liability when it was simply carrying out its duties under Iaaf rules would be unreasonable.
But Lord Hoffman added: "The Iaaf's system for control of drug abuse is plainly Draconian. It carries the risk of grave injustice to an athlete if a laboratory test should be wrong."
But the fact that a laboratory was not accredited did not necessarily mean the tests it carried out were wrong.