WW2 British Royal Navy Volunteer Reserve Officer's Service tunic.
A typical example of a wartime Junior R/N Officer's Service uniform jacket, dated to 1945. Made by Gieves Ltd. The gilt buttons are as those worn by the regular Royal Navy. This Officer was part of the RNVR, citizen sailors recruited for the duration. RNVR distinction was shown by the wavy gold lace on the cuffs. The Officer's matching cap cap be seen here.
WW2 British Royal Navy Officer's Service tunic.
This tunic is of a notably higher grade material than the previous example, which is perhaps not surprising as it is ranked to a Lieutenant Commander of the Royal Navy. Regular Royal Navy rank for the Service tunic was displayed by straight lace surmounting a loop. Uniquely to R/N tunics the medal ribbons are worn high up on the left shoulder, in this particular case displaying the General Service medal. The cap for this rank would have been that used by Junior R/N Officers.
For an overview of Royal Navy Service tunic ranks please see here.