A British army goat has been demoted in disgrace after it head-butted a drummer's rear-end during the Queen's birthday parade.

Billy, a six-year-old goat that is the mascot for the Royal Welsh Regiment in western Cyprus, was demoted to fusilier from lance-corporal Saturday after his superior officers ruled that his disruptive behaviour ruined a regimental parade at the British army base in Episkopy.

The parade included several international dignitaries who had been invited to celebrate Queen Elizabeth's 80th birthday.

Billy allegedly darted from side to side, throwing soldiers off their stride. But his worst offence was "trying to head-butt the waist and nether regions of the drummers," said Capt. William Rose.

British army spokesman Capt. Crispian Coates told the Canadian Press: "The goat, which has been the Royal Welsh Regiment's mascot since 2001, was supposed to be leading the march but would not stay in lineâ¦ He was reported for insubordination, and after consideration the commanding officer decided he had no option but to demote Billy."

The demotion was all the more shocking because Billy comes from a long line of British army blue bloods. His bloodline traces back to 1746 when his ancestor was donated to the Welsh regiment from the royal goat herd.

It wasn't immediately clear what impact the demotion would have.