How does longshore drift take place?

Longshore drift takes place as waves hit the beach at an angle. In the UK, the prevailing wind direction is SW so waves hit the beach at an angle from the South West. Waves carry sediment and pebbles through a number of transportation techniques, and move them up the beach at an angle then back down in a vertical motion as the waves retreat. This allows for a zig-zag pattern of sediment carried along the beach. 

As sediment is carried along the beach it often forms certain coastal features. Spits and bars can be formed as a result of longshore drift when the sediment is depositied as the waves lose energy.