This large class had it's roots late in WW1, when it wasrealised that no existing destroyer flotilla leaders could keep pace with the new, fast "R" class destroyer. Because the "R" and "S" classes' names had run into "T" and "U" names, thus the "V" class was thus born, and using the same machinery as the "R" class to speed construction, and on a greater displacement, were slightly slower.
Originally only 5 ships were ordered, as leaders, but due to incorrect reports of a powerful, new German destroyer type, a further 25 were ordered, but lacking the flag facilities of the 5 original ships. 2 allocated to Thornycroft were built to a modified design, but still within the Admirality's specifications.
These follow on ships had the gun from between the funnels, Q, moved to a superfiring position over A gun on a shelter deck to become B gun. This gave it a greater arc of fire, and a higher command.
The designed twin single 2pdr pom-pom AA armament was soon changed to a single 12 pdr AA, for both AAA and illuminating targets with starshell, and by opting for a 3 boiler A, B + X, Y gun arrangement, they were quite a bit shorter that preceding designs of A + Q + X, Y gun arrangement, and were also very economical steamers.
Twelve of this class could be modified to minelayers in under 24 hours, by removing Y gun, the after tube bank and fitting 60 mines, and could be distinguised by having minelaying chutes in the stern.
When the next order was placed, a triple torpedo tube mount was available, and so these 21 ships ordered were 1 "V" class and 20 "W" class. Again, those ships built at Thornycroft were built to that builders designs, the large, flat sided funnels common to the yard being a good identification feature, and an increase in beam was less apparent, to accomodate modified machinery.
The next order was in 1918 for 16, later 38 modified units, to ship the heavier 4.7" LA gun, which had not been shipped earlier due to topweight fears, and this same reason reversed the 12 pdr AA gun back to two 2 pdr AA guns in this class.
To enable some of these ships ( the group 2 modified "W" clas ) to have the bridge moved aft, the boiler arrangements were reversed to having the large boiler romm forward, wit 2 boilers and the small one for 1 boiler aft. Although decreasing watertight sub-division, and needing the 2pdr AA guns moved forward, this did allow for a drier bridge. Thus, the two classes could be distinguished by the "V" and "W" and group 1 modified "W" class, except Thornycroft units, having a tall thick funnel forward and a short thin one aft, whereas the group 2 modified "W" again except the Thornycroft units, having a tall, thin forward funnel and short thick one aft, due to again reversing the boiler arrangements!
At the armistice, 38 ships of all classes were cancelled, and other existing orders were completed in a rather londer stretch of time, the last not entering service until 1925.
In 1920, most "V" class had the twin tubes replaced by a triple unit, except Vimy, Vanoc, Velox, Versatile and Vortigern whch only had triple forward units, to become 5 tube ships.
One ship, a "V" was lost during the first World War, and 2 were lost in the Baltic manouvers post war against Red Russians, Five "V" and one "W" were scrapped interwar, and Walrus was lost en-route to a refit when she was grounded and written off.

With the worsening political situation in the late 1930's, and new destroyers replacing the "V" & "W"s in the flotillas, it was decided to start a wholesale conversion of units into set types of escorts, Fast AA escorts, or "Wairs", Short range escorts for East coast duties, and Long Range escorts for Atlantic and Mediteranean runs. For the most part, the LA weapons and their directors and the torpedo tubes were suppressed in place of depth charges, radar, AA guns and later Hedgehog depth charge throwers.
Those vessels not altered had the aft tube bank replaced by a 12 pdr AA gun, and carrier 2/4 x 1 x 20mm AA and
1 x 4 x 0.5" MG AA.

1:600 Vega, showing new bridge, twin "B" and "X" 4" AA and quad 0.5" MG, later 20mm cannons. 20mm cannon were also later fitted in the wings © Andrew Arthur

1:600 HMS Walpole, with 3 x 4.7", 1 x 12pdr and extra DC stowage. Note the en-echelon 2 pounders to allow free fire on both beams © Andrew Arthur

1:600 HMS Watchman, with fore-funnel struck, hedgehog in "A" position, a 2 pounder bow-chaser, 12 pdr aft and DC stowage amidships © Andrew Arthur