[Would you like to see this in-game?]
TL;DR: A Russian purchased Vickers Medium Mk. II. Later dug in and repurposed as a bunker.
Before the Soviet Union began to develop their own medium tanks, they had to get an idea of what the heck they were actually doing. So, to better understand the medium tank design, they purchased at least 15 Vickers Medium Mk. II in 1931 for evaluation. If the results were satisfactory, the Soviets would purchase licenses for production. The Mk II’s they received were made from Australian spares and thus shared the same flat, cupola-less turret. The Hotchkiss machine guns that came with the tanks were replaced with Maxim machine guns. Also, only a single Mk. II came with its 3-pounder cannon. The reason for this is likely because only a single complete vehicle was necessary for testing and, since they had replaced the machine guns, they probably intended to replace the main weapon as well. That being said, I cannot find any mention of this actually being carried out. The Soviets dubbed these vehicles the “English Workman”. Obviously, the Red Army wasn’t satisfied with the Workman and licenses were not pursued. They were repurposed as training vehicles and served with the Red Army in this role until 1938 when the order was given to turn them into bunkers or "БОТ"s (бронированная Oгневая Tочка), a number of them being sent to the Karelian Isthmus. Six of these bunkers were easily overrun by Finnish forces at the outbreak of the Continuation War. These vehicles were not recovered as they were deemed worthless. Another three Workmans awaiting conversion into bunkers were captured by German forces in September, 1941, along with three T-18s there for the same reason.
Place In War Thunder:
There are many who advocate for the addition of the Vickers Medium tanks, myself included. The English Workman, while not really directly inspiring any Russian vehicles, likely did teach the Soviets a little bit about medium tanks. It’s also just a really interesting variant of the Medium Mk. II. In-game, the vehicle would essentially just be a worse Independent, being slower and having even less armor. It’d have a few saving graces though. The ability to sling APHE from a hull-down position every 3 seconds is not something to underestimate. In the right position, the Workman can easily hold a sightline by itself. If the Workman is moving and finds itself having to engage another vehicle, the Workman is inherently more likely to come out on top due to its shoulder stabilizer. I think the Workman would fit best as a Rank I, 1.0 event premium as only a single one had access to a main weapon.
Armament: QF 3-pounder and 4x-6x Maxim Machine Guns (Might have not had its Vickers machine guns replace by Maxims)
Dimensions: 5.33m, 2.78m, 2.68m (L,W,H)
Ammunition: Same as the Independent in-game.
Three Workmans and T-18s captured by the Germans while awaiting bunker conversions:
The third Workman from the left:
Tank Encyclopedia - The Online Tank Museum
Pre-war Soviet BOT Tanks - Tank Encyclopedia
Vickers Medium Mark II - Wikipedia
Vickers Medium Mark II