What is the legal test for withdrawing an admission of fact?

Rule 31(5) provides that admissions of fact, whether deemed or actually made, cannot be withdrawn except by consent or with leave of the court. The principles to be drawn from the authorities that govern an application to withdraw an admission of fact are perhaps best set out in Hamilton v. Ahmed (1999), 28 C.P.C. (4th) 139 (B.C.S.C.) [paragraph] 11: 1. That the test is whether there is a triable issue which, in the interests of justice, should be determined on the merits and not disposed of by an admission of fact. 2. That in applying that test, all the circumstances should be taken into account including the following: 3. That the admission has been made inadvertently, hastily, or without knowledge of the facts. 4. That the fact admitted was not within the knowledge of the party making the admission. 5. That the fact admitted is not true. 6. That the fact admitted is one of mixed fact and law. 7. That the withdrawal of the admission would not prejudice a party. 8. That there has been no delay in applying to withdraw the admission.