Godolphin trainer Mahmood Al Zarooni has been summoned to appear at a British Horseracing Authority hearing after two of his horses tested positive for a banned substance.

The BHA will hold an inquiry on August 16 after urine samples taken from Mariner's Cross and Lyric Of Light were found to have contained traces of the prohibited propoxyphene.

Mariner's Cross' sample was taken after he won the Wood Ditton Stakes at Newmarket on April 19 while Lyric Of Light tested positive after finishing last in the 1000 Guineas on May 6.

The BHA must now determine whether Al Zarooni, who could face a hefty fine, breached racing rules.

Both horses also face disqualification from their respective races.