From its beginnings, St John Ambulance employed ranks and insignia to distinguish grades within its membership and management structure; these were extended across the wider organisation following its merge with the St John Ambulance Association to form St John Ambulance. Based upon the British Army officer and the British Army other ranks structure and insignia, the original ranks and insignia have been subject to several modifications over the history of the organisation. The basic "star" or "pip" has at its centre the eight-point Maltese Cross, the badge of the Order of St John. The crown used is also that of the Order. At the higher general list ranks, crossed stretchers are used rather than the crossed sword and baton of military use. Insignia are in silver, again symbolic of the Order of St. John. Also, officers who hold rank within the organisation at or above R4 wear a cockade in their hat (women) and have a silver bar (men), however at or above R3 wear a cockade and tuft (women) and silver bar and Wort cap (men). Since the mid-1990s the former "Senior NCO" and "Warrant Officer" ranks have been abolished. These ranks, whose titles were "Staff Sergeant", "Corps Sergeant Major", and "County (or District or Bailiwick) Sergeant Major" were deemed too militaristic in form although a few previous incumbents remain. Their demise has gone hand in hand with a lowering of emphasis on parading and drill. The county Sergeant Major, if the county has appointed one, wears member rank slides and Warrant Officer Class 2 (St John Crown in laurel leaves) arm badges on the bottom of each arm. Nurses used to wear Rhodium Metal bars on their Shoulder Straps. A red enamelled bar denoted a State Registered Nurse (SRN). A purple enamelled bar denoted a State Certified Midwife (SCM) and/or a Nurse on the Special Part of the State Register i.e. psychiatric or learning disability). A green enamelled bar denoted a State Enrolled Nurse (SEN). Their use was abandoned in the mid-1990s. In 2012, one Warrant Officer Class 1 (wearing Royal Arms badges in silver on both arms) was appointed at National HQ to advise on ceremonial matters across St John Ambulance. In December 2013, as a result of the rank review, a simplified rank structure was introduced, being fully implemented by the end of March 2014. The aim of the new rank structure is to ensure that