People often ask, “what is the easiest way of getting taps out of a basin, that have been there for decades?”

There is no ‘easy’ way, but if you use this set of instructions, the outcome should be favourable.
Can the basin to be taken off of the wall? – This will help a great deal.
Clean the exposed thread of the tap with a brush that you would use on your suede shoes.
Plenty of WD40 and maybe a SMALL amount of heat on the nut and thread. (being careful not to aim at the basin ceramic).
Leave if for a while and go back to it later.
Repeat the exercise. While still warm try undoing the nut, while restraining the topside of the tap.
Remove the nut completely.

Assuming that an old fashioned plumber will have ‘set’ them into the basin with a jointing compound that will now have the strength of concrete… 
Give the bottom of the tap a LIGHT knock with a soft faced mallet, to shock the area. NOT SO HARD THAT THE CORNER OF THE BASIN CRACKS OFF!
If this hasn’t worked, move on to the next paragraph.

GET SOME GOOD GLOVES FOR THIS SECTION.
Presuming the sink is upside down and resting on a surface that will not scratch the top of the basin or bend the shafts of the taps.
A liquid to break down this compound like “spirit of salts” (from your local chemist) can be poured directly onto the area.
It will fizz and chew into the ‘bonding’. DON’T GET IT ON YOUR SKIN.
Rinse with water and scrape away at the compound with a bradle and try the shock tactic again…
Repeat as necessary.
They will come out eventually.

We normally allow a day or two when doing this for customers who give us a complete basin.

If you get stuck call us BEFORE you break something in half.
And if all else fails, it is easier to ‘weld’ bits onto the tap, than it is to glue a basin back together!

Good luck.