<p>A lock for securing a window or door includes a locking pin (6) formed as part of a "locking plate (2) and which is securable to a moving part (MP) of the window or door by a pair of screws (10). A combination lock member (4) is securable to a stationary part (SF) of the window or door using a fixing plate (12). The combination lock member (4) has a plurality of combination dials (26) that are independently rotatable about a common axis and houses a locking column (30) that is biased towards a locking position where it engages with the locking pin (6) when the window or- door is closed. The locking column (30) is movable between the locking position and a retracted position where it does not engage with the locking pin (6) when the window or door is closed only when the plurality of combination dials (26) are in a predetermined alignment. When the window or door is closed, the locking pin (6) is received in an opening (40) in the combination lock member (4) and engages with the locking column (30) when the locking column is in the locking position to prevent the opening of the window or door.</p>
