Military tanks have traditionally been very heavily armoured and therefore limited to a maximum speed of about 35mph.
Today’s invention is a tank which is soft-skinned and thus light enough to move very fast and not require enormous tracks.
Instead of an overall coat of plating, the main gun carries a multi-layer composite shield.
Sensors on the vehicle detect incoming missiles (as currently happens with systems like this) and direct the gun turret to spin around so that the shield can be powered outwards along the barrel in time to act as an offset-detonation ‘skirt’.
This movement might best be generated by using railgun-type magnetic coils attached to the outside of the barrel.
The turret might accommodate two barrels and shields in order to provide better coverage for the entire vehicle.