how to remove washbasin taps ?

If the sink is porcelain then great care has to be taken.
Using a basin wrench (from a merchant) you need to turn the backnut (the one pressing against the porcelain (anti clock wise ) Once these are loosened undo the tap connectors and remove the taps. Depending on the age of the taps you may need tap extenders to make up the difference in the length of the thread. They are not so expensive but a new sink is, take care.

Plumbo
October 2011