Ceramic tile adhesive (whats best)

[ray bush]

I\'m having to tile over ceramic tiles which are sound ,i need to know what the best adhesive is for this job ,or can i just use a B&Q brand ?.The walls are all sound and will be de-greased prior to the new tiles being put over the old.
I\'m sure that when i did this before (quite a few years ago) i just used a normal adhesive.
Any views ?.

Thanks

[The Builder]

Certainly Ray. B&Q brand is as good as anything else :o)