This 2003 Prince William 21st birthday 5 pounds coin cover is a first day cover by Mercury Covers. It marks the 21st birthday of Prince William and hosts a Guernsey five pounds coin and Royal Mail stamps. The brilliant uncirculated coin features HRH Prince William of Wales and the stamps show his portraits. Postmark cancelled HRH Prince William 21st Birthday St Andrews Fife Scotland 17th June 2003.