5. Not much assistance is to be gained, I think, from observations that are to be found in reported cases as to the import of the word "contingent", and I shall refer to one only. In In re William Hockley Ltd. (1962) 1 WLR 555, at p 558 , Pennycuick J. suggested as a definition of "a contingent creditor" what is perhaps rather a definition of "a contingent or prospective creditor", saying that in his opinion it denoted "a person towards whom, under an existing obligation, the company may or will become subject to a present liability upon the happening of some future event or at some future date". The importance of these words for present purposes lies in their insistence that there must be an existing obligation and that out of that obligation a liability on the part of the company to pay a sum of money will arise in a future event, whether it be an event that must happen or only an event that may happen. A building contract creates, as soon as it is entered into, an obligation upon the building owner to pay the contract price, either as a whole upon a future event or, more usually, by progress and final payments each of which is to be made on a future event. The event or events may not happen, but if and when one of them does happen the building owner, by force of the contractual obligation, must pay the builder a sum of money. It is, I think, nothing to the point that the event may be complex, as where the payment is agreed to be made when the whole or some part of the work has been done to the satisfaction of an architect as expressed in a certificate or to the satisfaction of an arbitrator as expressed in an award: the building owner is bound from the time the contract is made to pay money to the builder upon a contingency; and that in my opinion makes the builder a contingent creditor of the owner. (at p459)