While these regiments have other distinguishing features, a simple method of distinguishing members of the different Guards units by their appearance is by the spacing of buttons on the tunic. The ascending number of buttons also indicates the order in which the regiments were formed, although the 1st Regiment of Foot Guards, an ancestor of the Grenadier Guards, is younger than the regiment that now takes the name of the Coldstream Guards; the oldest continuously serving regiment in the regular British Army (there are older regiments in the Army Reserve). There are various other distinguishing features of the uniforms of the regiments, such as the colour of the plume, which side it is worn on the bearskin, the collar badge and the shoulder badge. When all five regiments parade together, they are in the order of Grenadier Guards on the right flank, then Scots Guards, Welsh Guards, Irish Guards and Coldstream Guards on the left flank. This is because although the Coldstream are ranked second in seniority, their motto is "Nulli Secundus" ('Second to None'). The five regiments of Foot Guards, lined up as they parade   The first three regiments each have a separate incremental company, which keep custody of the colours and traditions of the currently dormant 2nd Battalions. These companies perform ceremonial and security duties in London. The Foot Guards have a role as the primary garrison for the capital, for the military security of the Sovereign, and for ceremonial duties in London and occasionally elsewhere. Two battalions are appointed for public duties, with a third from a line infantry regiment since 1996 (and occasionally previous to that year). These provide the Queen's Guard, the Tower of London Guard, and sometimes also the Windsor Castle Guard. The Guards Battalions on Public Duties are located in barracks close to Buckingham Palace for them to be able to reach the Palace very quickly in an emergency. In central London, a battalion is based at Wellington Barracks, Westminster, about 300 yards from Buckingham Palace. However, as of 2010, the independent incremental companies of the Grenadier and Coldstream Guards (all on permanent public duties) have been moved from Chelsea Barracks to the Royal Artillery Barracks in Woolwich. While F Company, Scots Guards, are now permanently based at Wellington Barracks alongside the resident infantry battalion. The Guards Battalion stationed at Windsor generally provides the Windsor Castle Guard. The Windsor battalion is at Victoria Barracks, a quarter of a mile south of the Castle. The Guards Division received a new battalion following the restructuring of the army in 2004, when the London Regiment became the first Territorial Army unit as part of this division.