it. The plaintiff who was the last in the chain of purchasers sought to rely on laches and acquiescence. This was unavailing since the heirs did not know of their right over the years. In Yusuff v. Dada [1990] 4 NWLR (Pt. 1146) 657, upon the death of the land owner intestate, four persons applied for and obtained letters of administration to administer his estate. In the meantime, the head of family who was one of the administrators, had sold the land to the defendant. After he had completed a building on the land, the administrators sued him to recover damages for trespass and an order of injunction to restrain him from entering the land. Their action failed because they had knowledge of the defendant‟s building but pretended to be blind. Agbaje JSC added that three of the four administrators were affected by the notice of the head of family who sold the land to the defendant. 4. The landowner must know of the improver’s mistake. The case of Faloju v. Amosu (1983) NSCC 456 provides a quintessence of this element. In that case, a family allotted its members a parcel of land to erect a building. At a time when the allottee had built a house half-way, he sold it to a building contractor. The building contractor completed the building with the knowledge of members of the family. It was held that the family could challenge the purchaser‟s occupation because they were entitled to assume that the purchaser was building for the allottee. On the issue of laches, Aniagolu JSC said: “It took the family two years of attempts at extra-judicial settlement involving the Bale and Chiefs of Ife… before finally deciding on going to court against the defendant. It does not appear to me that the plaintiffs in these circumstances, could be said to have slept on their right for the