The U and V class was a class of sixteen destroyers of the Royal Navy launched in 1942–1943. They were constructed in two flotillas, each with names beginning with "U-" or "V-". The hull was nearly identical to the preceding ships of the S and T classes, but the U and V class ships had different bridge and armament fits. The flotillas constituted the 7th Emergency Flotilla and 8th Emergency Flotilla, built under the War Emergency Programme. These ships used the Fuze Keeping Clock HA Fire Control Computer.

HMS Undaunted was a U-class destroyer of the British Royal Navy that saw service during World War II. She was later converted into a Type 15 fast anti-submarine frigate, with the new pennant number F53.