Upholder/Victoria-class submarine
The Upholder/Victoria-class submarines, also known as the Type 2400 (due to their displacement of 2,400 tonnes), are a class of diesel-electric submarines built in the United Kingdom in the 1980s to supplement the nuclear submarines in the Submarine Service of the British Royal Navy. The boats were originally named the Upholder class, after the most renowned vessel of the former U class.
Source: Wikipedia — Upholder/Victoria-class submarine (CC BY-SA 4.0)