The officious bystander test:
Had an officious bystander been present at the time the contract was made and had suggested that such a term should be included, it must be obvious that both parties would have agreed to it.
Shirlaw v Southern Foundries [1939] 2 KB 206
The man on the Clapham omnibus is a hypothetical reasonable person, used by the courts in English law where it is necessary to decide whether a party has acted in the way that a reasonable person should - for example, in a civil action for negligence. The man on the Clapham omnibus is a reasonably educated and intelligent but nondescript person, against whom the conduct of the defendant can be measured. This concept was used by Greer LJ in the case of Hall v. Brooklands Auto-Racing Club (1933)
Both can be used still