It sounds like the tank is on its way out and it certainly should *not* be
leaking.

just to clarify the tank is not leaking (we have had many people looking in
and around it), we were just told that there may be a minor problem with the
brickwork which the tree could "get into" and then cause the tank to crack
and leak. We are intending to have it replaced but not for a few years, we
just want to get rid of the tree, partly because of the potential problem
and partly just because it doesn't "do" anythign for the garden - whilst I
am a firm believer in teh fact that trees are good I also have a finite
sized garden and would rather replace this particular tree with something
smaller and more interesting! It is not a venerable old oak, just a boring,
rather sickly looking birch
So, can any one suggest something which is unlikely to damage our tank
please?

--
Hayley
(gardening on well drained, alkaline clay in Somerset)