The British Army does not usually issue the No 1 dress uniform to all soldiers, most use the No 2 dress uniform for formal occasions. Small stocks are held regimentally, however, for select uses and on occasions soldiers may privately purchase a uniform for a particular event such as their marriage. These uniforms are very expensive to have made up, and so older uniforms are recycled and updated with new insignia to defray the costs and that is what we are looking at an example of today:

This smart No 1 dress tunic is made of dark blue wool, with red piping to the epaulettes on each shoulder:

What makes the tunic particularly interesting however is the design of the staybrite buttons, which is that adopted by the Royal Logistics Corps on its foundation in 1993:

The tunic itself dates from the 1950s however:

No. 1 dress originated in the “undress” uniforms (‘blue Patrols’) worn for semi-formal or ordinary duty occasions in the late 19th century. It was first issued in its current form for the 1937 Coronation, intended as a cheaper alternative to the full dress uniforms that had been generally withdrawn after 1914. It became known as No. 1 Dress in 1947. Army units participating in the 1953 Coronation wore the new uniform as a temporary issue. Since then it is only worn for the most formal of occasions such as when a regiment is providing a guard at Buckingham Palace, as seen here where 3 Regiment RLC can be seen wearing the uniform:

The rank insignia worn on this uniform is gold braid on a red backing:

It is impossible to say if this tunic is one that has been prepared by the regimental tailor for ceremonial duties, or an example purchased second hand by a member of the regiment who has changed the insignia for an event such as his wedding, however I tend towards the former suggestion. Either way, this is an unusual and very smart piece of uniform and one not commonly seen, even within the regiment these days.