A container comprising: a main body defining a chamber for receipt of material and an access opening to the chamber; a door member mechanically linked to said main body by a hinged connection (20, 21), the hinged connection having a hinge axis and permitting rotation of the door member relative to the main body about said hinge axis between a first position in which the access opening is open and a second position in which the access opening is closed, the hinged connection also permitting translation of the door member relative to the main body in a direction substantially parallel to said hinge axis to an intermediate position between the first and second positions; wherein the door member may only move from the second position to the first position via the intermediate position; and a lock assembly (58; 82), characterised in that the lock assembly comprises: an engagement member (64; 84) having a first portion (66; 86) which is fixed to either the door member or the main body and a second portion (68; 90) moveable relative to the first portion (66; 86) between a first configuration, in which said translational movement of the door member from said second position to said intermediate position is permitted, and a second configuration, in which said translational movement of the door member from said second position to said intermediate position is substantially prevented; wherein said second portion (68; 90) is biased towards said second configuration; and an actuation member (63; 98) which is contactable with said engagement member (64; 84) so as to move said second portion (68; 90) from said second configuration to said first configuration. a main body defining a chamber for receipt of material and an access opening to the chamber; a door member mechanically linked to said main body by a hinged connection (20, 21), the hinged connection having a hinge axis and permitting rotation of the door member relative to the main body about said hinge axis between a first position in which the access opening is open and a second position in which the access opening is closed, the hinged connection also permitting translation of the door member relative to the main body in a direction substantially parallel to said hinge axis to an intermediate position between the first and second positions; wherein the door member may only move from the second position to the first position via the intermediate position; and a lock assembly (58; 82), characterised in that the lock assembly comprises: an engagement member (64; 84) having a first portion (66; 86) which is fixed to either the door member or the main body and a second portion (68; 90) moveable relative to the first portion (66; 86) between a first configuration, in which said translational movement of the door member from said second position to said intermediate position is permitted, and a second configuration, in which said translational movement of the door member from said second position to said intermediate position is substantially prevented; wherein said second portion (68; 90) is biased towards said second configuration; and an actuation member (63; 98) which is contactable with said engagement member (64; 84) so as to move said second portion (68; 90) from said second configuration to said first configuration. an engagement member (64; 84) having a first portion (66; 86) which is fixed to either the door member or the main body and a second portion (68; 90) moveable relative to the first portion (66; 86) between a first configuration, in which said translational movement of the door member from said second position to said intermediate position is permitted, and a second configuration, in which said translational movement of the door member from said second position to said intermediate position is substantially prevented; wherein said second portion (68; 90) is biased towards said second configuration; and an actuation member (63; 98) which is contactable with said engagement member (64; 84) so as to move said second portion (68; 90) from said second configuration to said first configuration.