It appears to me to be the law that a reversioner, such as the 2nd respondent, cannot sell his reversionary interest, that is his particular estate, as fee simple while another person is in possession of the land. He must first either first recover possession from that other person in possession or sell his reversionary interest subject to that person’s possession. For what the reversioner has in such a case is the freehold reversion subject to the possession in another person and not a fee simple absolute free from incumberances. It must be noted that interests in land, whether legal or equitable, are carved out as it were on a plane of time. Any holder of a particular interest or estate who attempts to sell more than the quantum of his estate will be caught by the maxim: nemo dat quod non habet (no one can give or sell what he has not).
– Nnaemeka-agu, JSC. Ude v. Nwara (1993)