Researcher David Lister has posted an interesting article about British use of the 3.7 AA gun in the direct fire anti-tank role.
“A question I often see asked is “Why didn’t the British use the 3.7″ AA gun like the German 88?”. By that they mean why not crank its elevation down to 0 degrees and start knocking out tanks. This is partially supported by Wikipedia’s entry on the subject that reads:
“The 3.7″ was inherently unsuitable as an anti-tank gun. It was big and heavy, 2 tons heavier than the German 88, making it tactically unsuitable for use in forward areas. Additionally, heavy AA Regiments equipped with the 3.7″ gun were relatively few in number in the field army and controlled by Corps or Army HQ, or at even higher level HQs, and command of them was not often devolved to the commanders at Divisional level where the anti-tank role might be required.”
The implication is that the 3.7″ AA gun was only ever used in desperation before being overrun. As you might guess this isn’t entirely true. Certainly pre-war, up until some time in 1938, crews were trained in direct fire roles. However the rapid re-arming of the British forces meant that this training was dropped. The mounts also had a part to play. With the MKI being a complex piece of equipment, the gunners faced forward. In the MKII (the static mount) the gunners were facing in towards the gun mount, and finally in the much simplified and lightened MKIII mount the gunners were facing towards the rear of the gun.”
Tank and AFV News 