Which United Kingdom Royal Navy rank is this?

Officers of the Royal Navy wear their rank insignia on their sleeves and/or their epaulettes. Commissioned ranks commence with Sub Lieutenant and ascend to Admiral of the Fleet.

Rank insignia consists of bands of gold braid, the top band being surmounted by a curl. Sub Lieutenants have one band, Lieutenants have two, Lieutenant Commanders have two with a narrow band between, Commanders have three, and Captains have four.

After Captain there is the rank of Commodore which is denoted with a broad band and curl, Rear Admirals add another band above the broad band, Vice Admirals having two, Admirals three, and Admiral of the Fleet four bands above the broad band. Rear Admiral and above epaulettes are different and have a star or stars and crossed swords and a crown.

United States Navy has similar insignia, with a star replacing the curl, and the ranks from Lieutenant upwards are much the same.