It's a Knockout was a late 70s gameshow in which adults got to run around firing water cannons, wear big suits, jump over bouncy castles and fight each other using big foam weapons. A bit like a real war, but in the name of fun.
Stuart Hall presented and commentated on it, and you just HAD to join in laughing with him. There were times when a contestant may have been drowning in foam, being hit by huge spongey sticks and limping badly and all Stuart Hall could do was laugh REALLY loudly. It was classic telly.
I remember they filmed an I.A.K. near my house once, and my dad took me to see it. It took about 3 hours to film, and was quite boring to witness I'm afraid. Stuart Hall was there though, so it wasn't all bad.