A tamper-evident closure (10) for a container (20) is provided. The closure (10) comprises a first portion (25) including inner (35) and outer (45) parts, and a second portion (30). The outer part (45) is movable relative to the inner part (35) from a first position in which the outer part (45) is immediately adjacent the second portion (30) to a second position in which there is an empty unobstructed gap (G) therebetween. The inner (35) and outer (45) parts are adapted to become irreversibly locked in the second position so that the outer part (45) cannot be moved back to the first position to close the gap (G). A combination of such a closure (110) with an in-bore filament (100) connectable to a container (120) is also provided.