1. This appeal concerns a piece of land in Sai Kung (the “Disputed Land”) jointly owned by three brothers who died respectively in 1991 or 1992, 1997 and 1999 (the “Three Brothers”). The Appellant is the personal representative administering the estates of the two younger brothers. The 1st and 2nd Respondents are the children of the eldest brother and have inherited his share in the Disputed Land. The 3rd Respondent is the son of the 1st Respondent. 2. Since the 1970s, there had been an understanding among the Three Brothers and the 3rd Respondent that the latter could use and own the Disputed Land and build a house thereon when he became an adult (the “Common Understanding”). The Common Understanding did not include an assurance that the Three Brothers would leave the Disputed Land by will to the 3rd Respondent. Knowing about the Common Understanding, the 3rd Respondent started carrying out various building works on the Disputed Land since the 1980s. He also erected two buildings on the Disputed Land in 2002 and 2003 (the “Structures”). 3. The Appellant brought an action against the Respondents, seeking an injunction to restrain them from carrying out building works on the Disputed Land and requiring them to remove the Structures. Based on the Common Understanding, the Respondents argued that the 3rd Respondent is beneficially entitled to the Disputed Land, and the Appellant is prevented from claiming relief due to the doctrines of common intention constructive trust, proprietary estoppel, estoppel by acquiescence, and promissory estoppel. The 1st and 2nd Respondents counterclaimed against the Appellant for one-third of the rental income of a house built on land adjacent to the Disputed Land (the “House”). The House is jointly owned as to one-third by the 1st and 2nd Respondents and as to two-thirds by the Appellant as tenants-in-common in undivided shares. 4. The Court of First Instance (“CFI”) dismissed the Appellant’s claims and held that the 3rd Respondent is the sole beneficial owner of the Disputed Land, and the Appellant is a constructive trustee holding a two-thirds interest therein for him. The CFI also upheld the counterclaim of the 1st and 2nd Respondents. The Court of Appeal (“CA”) set aside the CFI Judgment and remitted a number of questions that raise both factual and legal issues to the CFI Judge. 5. On the Appellant’s application for leave to appeal, the CA held that the questions raised are reasonably arguable but decided to adjourn the leave application, pending the CFI’s determination of the remitted issues. The Appellant then successfully obtained leave to appeal to this Court from the Appeal Committee. 6. The issues on appeal related to the scope and timing of the “detrimental reliance” required to establish a proprietary estoppel and to whether the counterclaim for occupation rent and rental receipts by the 1st and 2nd Respondents as co-owners against the Appellant was made out. The requirement of “detrimental reliance” in proprietary estoppel 7. The issue was whether there was sufficient detrimental reliance by the 3rd Respondent on the Common Understanding prior to the death of all of the Three Brothers to give rise to a proprietary estoppel against the Appellant as the personal representative administering the estates of the two younger brothers. 8. The Court held that where there is a lack of the necessary detrimental reliance by the promisee prior to the death of the promisor, the promise or assurance by the promisor must be taken to have lapsed upon the latter’s death. If a promisee can establish a proprietary estoppel based on sufficient detrimental reliance incurred prior to the death of the promisor, his/her interest so created would prevail over the interests of the testamentary beneficiaries or of the next of kin (under the Intestates’ Estates Ordinance (Cap.73)). 9. On the facts of the case, the steps taken by the 3rd Respondent prior to the death of the Three Brothers to improve the Disputed Land constituted sufficient detrimental reliance by him upon the Common Understanding. The Court therefore ordered the Appellant to transfer her two-thirds interest in the Disputed Land to the 3rd Respondent. The payment of occupation rent to co-owners of land in cases other than partition or ouster in the absence of an agreement 10. The issue was whether the Appellant should be ordered to pay the 1st and 2nd Respondents occupation rent and rental receipts, despite the fact that they had not been ousted (i.e., excluded) from the House and there were neither partition nor analogous proceedings in being, nor any agreement between the parties giving rise to a duty to account. 11. The Court held that the CA’s reference to a “modern approach” that a court will order a payment of occupation rent even if there is no ouster simply when it is necessary to do equity between the parties is not supported by the existing authorities. 12. In a case where partition or analogous proceedings have been instituted but no co-owner has been ousted from the property in question, an equity in favour of one of the co-owners who spent money on substantial repairs and lasting improvements may be recognised while debiting the other co-owner with an occupation rent to set off the expenditure appropriately incurred. This reciprocally balances the parties’ interests in the distribution of the proceeds of sale of a co-owned property. 13. On the facts of the case, the Court held that the 1st and 2nd Respondents had failed to show any basis for claiming occupation rent or an account of rent. The counterclaim was therefore dismissed and it was unnecessary to remit the issue of building expenses incurred by the Appellant to the CFI for determination. DISPOSITION: 14. Accordingly, the appeal was unanimously allowed, the CA’s Orders were set aside and in their place, the Court dismissed the Appellant’s claim against the 1st, 2nd and 3rd Respondents and ordered her to transfer her share of the Disputed Land to the 3rd Respondent; the Court also dismissed the claim of the 1st and 2nd Respondents for an account of rent, making necessary consequential Orders.