An elderly woman is in a serious condition following an accident involving a motorcycle that was escorting the Duke and Duchess of Cambridge.

Prince William and Kate had been returning from a horse racing event at Royal Ascot, when it is believed a motorcycle riding alongside their vehicle collided with he 83-year-old.

The woman has been taken to hospital and remains in a serious condition.

It is believed the Duke and Duchess have sent the woman flowers and plan to visit her soon.

4KQ 693AM Brisbane