and if you are playing multiple brits with multiple sim cities?
Come on, admit it, the mortar pit is ridiculously OP.
Then that means that their whole team is largely immobile. A defensive line made out of mostly static emplacements and supporting units is the best counter against a team of knob-heads who can't communicate and just attack straight on across the whole line. So don't be a knobhead and get your team together and strike through at one point, then clean up the rest. You know, use tactics!