GINA Mangan, the apprentice who was set to partner rank outsider Diore Lia in Saturday's Investec Derby, has been prevented from riding in the Epsom feature by the British Horseracing Authority.

The 7lb claimer had been booked to ride the 1000/1 chance, who is trained by her boss John Jenkins, in the premier Classic as owner Richard Aylward was keen to generate publicity for Great Ormond Street Children's Hospital by running his homebred filly.