Portrait by Joseph Edgar Boehm ("Jubilee head").
The new design was struck as part of a new coinage in gold and silver to commemorate the Golden Jubilee of Queen Victoria, 1837-1887. Boehm adapted the effigy from his own Jubillee medal. This obverse proved unpopular and was only used until 1893.
There are two versions of the portrait, known as "Small Head" (smaller head, more of the Queen's body shown) and "Large Head" (larger head, at the expense of some part of the Queen's shoulders being truncated).