A cooking appliance, comprising: a pressure vessel having an opening surrounded by a peripheral edge portion; a lid pivotally coupled to said vessel and configured to move between an open position and at least a closed position; a locking mechanism, comprising at least one locking member, operably coupled to one of said lid or said vessel, wherein said locking member comprises a hook-shaped end portion; and at least one catch member, operably coupled to the other one of said lid or vessel, and configured to move between a locked position, where said locking member and said catch member are engaged so as to lockingly secure said lid relative to said vessel, and an unlocked position, where said locking member and said catch member are disengaged so as to release said lid relative to said vessel; wherein said hook-shaped end portion is configured to lockingly receive the at least one catch member; and a resiliently compressible seal member interposed between said lid and said peripheral edge portion of said opening, so as to fluidly seal said vessel when said lid is in said closed position, wherein said cooking appliance is adapted to affect said locking mechanism into an inoperable state at an inner vessel pressure greater than or equal to a predetermined pressure when in said locked position, in that the hook-shaped end portion is biased by the inner vessel pressure acting on an inner surface of the lid into a locking engagement with the catch member that cannot be overcome by a user, characterised in that said locking mechanism comprises a first locking member and a second locking member, operably coupled to opposing sides of one of said lid or said vessel, and a first catch member and a second catch member, operably coupled to respective sides of the other one of said lid or vessel, wherein said first locking member is operably coupled to said second locking member, so as to synchronise the movement between said first locking member and said second locking member. a pressure vessel having an opening surrounded by a peripheral edge portion; a lid pivotally coupled to said vessel and configured to move between an open position and at least a closed position; a locking mechanism, comprising at least one locking member, operably coupled to one of said lid or said vessel, wherein said locking member comprises a hook-shaped end portion; and wherein said hook-shaped end portion is configured to lockingly receive the at least one catch member; and a resiliently compressible seal member interposed between said lid and said peripheral edge portion of said opening, so as to fluidly seal said vessel when said lid is in said closed position, wherein said cooking appliance is adapted to affect said locking mechanism into an inoperable state at an inner vessel pressure greater than or equal to a predetermined pressure when in said locked position, in that the hook-shaped end portion is biased by the inner vessel pressure acting on an inner surface of the lid into a locking engagement with the catch member that cannot be overcome by a user, characterised in that said locking mechanism comprises a first locking member and a second locking member, operably coupled to opposing sides of one of said lid or said vessel, and a first catch member and a second catch member, operably coupled to respective sides of the other one of said lid or vessel, wherein said first locking member is operably coupled to said second locking member, so as to synchronise the movement between said first locking member and said second locking member.