Use a plunger which can be purchased from any plumbers merchant or hardware store
Pour a small amount of bleach into the plughole and leave overnight
Purchase some drain sticks and put these down the plug hole, leave overnight
DRAIN STICKS CLICK HERE
MAKE SURE YOU HAVE NOT PUT BLEACH IN IF YOU USE THIS OPTION OTHERWISE YOU WILL BURN YOURSELF
Place a bucket under the sink direcly under the U-Bend and unscrew it with caution.
Empty and wash the U-Bend to remove the blockage
If the blockage is in your toilet – CLICK HERE