For the purposes of the Misuse of Drugs Act 1971 ‘possession’ has two elements: the physical element and the mental element. The physical element involves proof that the thing is in the custody of the defendant or subject to his control. The mental element involves proof of knowledge that the thing exists and that it is in his possession. Proof of knowledge that the thing is an article of a particular kind, quality, or description is not required. For firearms a person may be in possession of a firearm if it is under his control even though he does not have physical possession of it. In the case of land, possession may be actual, when the owner has entered onto the land, or possession in law, when he has the right to enter but has not yet done so. Possession includes receipt of rent and profits, or the right to receive them.