Anyone know of a plastic sleeve product which will go inside an old clay
soil pipe? As far as I can tell the old pipe has about a 4" internal
diameter.

Details: I have come across an old soil pipe which is very badly
cracked - at least to the parts that I can see - and has small roots
growing in to it through the cracks. The ideal thing would be to replace
it with a new one but parts of the existing pipe are fairly inaccessible
without going to a lot of extra cost and would require damage to an
internal tiled floor that I may not be able to match with replacement
tiles.

So I wondered if it was possible to buy a plastic internal sleeve for
such old pipes. The idea is that the sleeve would support the walls of
the existing pipe, stop water leaking through the cracks, and provide a
good end to join on to the subsequent pipe.

That's the idea. Is there any product for a problem such as this? Unless
it is flexible I would only need a short length - say less than 2 feet.

James