A buckle for a harness used in a child safety seat comprising: a base part having a first magnetic element; a latch part configured to engage the base part; and a slide part having a second magnetic element and a third magnetic element moveably connected to the latch part and movable between opposing latched and unlatched positions, movement of the slide part to the latch position aligning the first magnetic element and the second magnetic element in a magnetically attracting configuration to attract the latch part into engagement with the base part, movement of the slide part to the unlatched position aligning the first magnetic element and the third magnetic element into a magnetically repelling configuration to urge the latch part out of engagement with the base part; wherein the base part comprises a flange (26, 27) engageable by a portion of the slide part when in the latched position to retain the latch part engageably connected to the base part; wherein the slide part comprises a catch slide the catch slide being bi-directionally moveable along a slide axis between the latched and unlatched positions and configured to engage a flange (26, 27) on the base part to retain the latch part in engagement with the base part when the catch slide is in the latched position, a first resilient element being provided to bias the catch slide toward the latched position, characterized in that the slide part comprise a magnetic slide, the magnetic slide being bi-directionally moveable relative to the catch slide in a direction parallel to the slide axis between engaging and releasing positions, a second resilient member being provided to bias the magnetic slide toward the engaging position, the catch slide configured so that continued movement of the magnetic slide in the direction toward the releasing position causes movement of the catch slide toward the unlatched position. a base part having a first magnetic element; a latch part configured to engage the base part; and a slide part having a second magnetic element and a third magnetic element moveably connected to the latch part and movable between opposing latched and unlatched positions, movement of the slide part to the latch position aligning the first magnetic element and the second magnetic element in a magnetically attracting configuration to attract the latch part into engagement with the base part, movement of the slide part to the unlatched position aligning the first magnetic element and the third magnetic element into a magnetically repelling configuration to urge the latch part out of engagement with the base part; wherein the base part comprises a flange (26, 27) engageable by a portion of the slide part when in the latched position to retain the latch part engageably connected to the base part; wherein the slide part comprises a catch slide the catch slide being bi-directionally moveable along a slide axis between the latched and unlatched positions and configured to engage a flange (26, 27) on the base part to retain the latch part in engagement with the base part when the catch slide is in the latched position, a first resilient element being provided to bias the catch slide toward the latched position, characterized in that the slide part comprise a magnetic slide, the magnetic slide being bi-directionally moveable relative to the catch slide in a direction parallel to the slide axis between engaging and releasing positions, a second resilient member being provided to bias the magnetic slide toward the engaging position, the catch slide configured so that continued movement of the magnetic slide in the direction toward the releasing position causes movement of the catch slide toward the unlatched position.