(EN) A closure 100 for a keg 14 (not shown) comprises a housing 160 and at least one valve 210 element that is movable with respect to the housing, inwardly into an open state and outwardly into a closed state. The closure also comprises a lock mechanism having a locking element 500 that is movable with respect to the housing and is capable of holding the valve element in the open state. The lock mechanism includes first 507,506320 and second 504,214 couplings at which the locking element and the valve element are mutually engageable. The lock mechanism is arranged such that when the locking element and the valve element are engaged at the first coupling, the locking element moves with the valve element as the valve element moves from the open state into the closed state. This movement of the locking element enables engagement between the locking element and the valve element at the second coupling, which engagement at the second coupling occurring on subsequent movement of the valve element into the open state to prevent the valve element returning to the closed state. In use, the closure allows the valve to be opened to allow the keg to be filled, closed to allow the keg to be transported and opened to allow the contents of the keg to be dispensed but then locks the valve open to prevent the keg being refilled.