Churchill's short barrels lend themselves to quick, instinctive shooting and he promoted a shooting method that, it can be argued, compliments his style of gun.
The practical methodology of Churchill's shooting style was to swing the gun with the bird as you mount, shooting the instant that the stock touches the shoulder and cheek. Many will say they do this but with most shooters (and I have coached a huge number who fall into this category), there is a hesitation before the trigger in pulled. Some use this to good effect to adjust the lead 'picture', and keep the gun swinging, but many are unconscious of the hesitation and stop or slow their swing during it.
The thinking shot might be forgiven in saying that without perceived lead, Churchill's method is bound to fail on any but the closest of targets.
I think the system works for many on all but long crossers because one rarely manages to keep the gun ON the target throughout the mount and is most likely playing 'catch up' in the final moments of the mount. This gives the gun accelerating swing in the final moments and, combined with one's body's 1/10 second reaction time, gives unperceived lead as one is pulling the trigger.
Personally, I don't get on with the system, I shoot 'BASC Method' most of the time but I find it helps those who simply can't see lead without stopping the gun.