The T18E2 Boarhound stemmed from the development of the heavy T18 Armored Car program.  In fact, the first T18E2 was actually the second proposed (but cancelled) T18 prototype vehicle.  The main difference was that the Boarhound was designed to mount a 57mm cannon instead of the 37mm gun fitted on the T18. Great Britain originally placed a large order (some references stating 2,500 vehicles) for the T18E2.  However, due to production delays, parts procurement problems, sub-par performance and changing attitudes toward heavy armored cars, only 30 Boarhounds were built and delivered to the British.