If you have any sort of interest in WW2 Finnish armour it won't be long before you come across the BT-42. This home-spun stop-gap tank was based on captured Soviet BT-7 chassis with a obsolete British 4.5 inch (114mm) field gun shoe-horned into a big boxy turret. Only 18 of these - largely unsuccessful - AFVs were built but despite this they remain of great interest to the modelling fraternity.
Mark's model is based on the UM 1/72 kit and I found it particularly interesting to see that his camo pattern - particularly the buff colour - seems to match the one I am using on my current Finnish T-34/85 project. Interpretations of this three colour pattern seem to vary quite a lot, chiefly with the grey being substituted for a light buff and the buff becoming a deep hazel brown. I personally lean more to the more subdued scheme Mark has produced here.
[Oh, incidentally. Mark used the blue Finnish Hakenkreuz that come with the UM kit, these are wrong. The Finns used the black version of this swastika on their armour at this time.]
On a historical note this stop-gap hybrid tank-to-SPG was quite common in WW2 and produced some very successful AFVs (one immediately thinks of some of the German SPGs in particular) but the Finns seem to have gotten it completely wrong in that they used the BT-42 - disastrously - in the direct fire AT role. The obsolete gun just was not up to the job and there are reports that multiple shots from it simply bounced off the sloped armour of the Soviet T-34 tanks.
The BT-42 was eventually replaced by the more adept German Stug III.
You can see more about Mark's BT-42 by visiting his review at missing-lynx.com
...Or you can read about the history of the BT-42 at Wikipeadia.