The Queen's horse Estimate has been stripped of its second place finish in this year's Gold Cup following a positive drugs test, a British Horseracing Authority (BHA) disciplinary hearing has ruled.

The post-race sample containing the prohibited substance morphine was the result of contaminated feed and the Queen's trainer Sir Michael Stoute will not face a financial penalty.

The BHA was satisfied all reasonable precautions were taken to avoid any breach of the rules.

But the rules of racing state that horses producing a positive sample for a prohibited substance should be disqualified from the relevant races.

Another horse trained by Sir Michael also tested positive for morphine after running, like Estimate, at Royal Ascot and was disqualified from its ninth place in the Buckingham Palace Stakes.

The BHA tweeted: "The horses have been disqualified from the races in question. No financial penalty has been imposed upon the trainer."

The organisation's disciplinary panel is meeting in London and hearing a number of cases involving horses that have tested positive for morphine.

Estimate was defending the Gold Cup title it won at Royal Ascot last year and was narrowly beaten in a thrilling race by Leading Light.

The Gold Cup win had made sporting history for the Queen as she became the first reigning monarch to own a winner of the coveted race.