There is no room to imply a long-stop date for completion of a conditional agreement where the agreement expressly contemplates uncertainty and the parties have agreed to wait until the condition can be met.
In Wong On Na v Harbour Well Development Limited ( HKEC 2) the plaintiff had agreed to buy a house in the New Territories from the defendant developer. The agreement made completion conditional on getting the necessary Certificate of Compliance from the relevant District Lands Office. The developer completed the building works and sought the certificate. A lengthy delay ensued (through no fault of the developer). The plaintiff sought to rescind and the developer counter-claimed for damages. The plaintiff alleged that there was an implied term that completion was to take place within a reasonable time (see Johnson v Humphrey  1 All ER 460). This claim failed. The agreement made it clear that the completion date was uncertain and depended on obtaining the certificate. This was outside the developer’s control; it had done all that it could to obtain the certificate. The developer was awarded damages representing the difference between the contract price and the market price at the date of the hearing (the market had fallen).