Broken clay soil pipe collar?

[rhamson]

Hello, we are having some groundworks done and have noticed that where the concrete has been partially removed around the bottom of the soil pipe (from toilet etc), it has exposed a gap at the end of the plastic pipe which is leaking - it looks maybe like the collar on the lower clay pipe has been partially broken? Can this just be patched up e.g. with mortar/cement, or if not what is the best fix?

Possible options I've come across:
1. Adaptor that sits inside clay pipe to fit plastic pipe into;
2. Replace lower length of plastic pipe with longer piece that finishes further down within clay pipe, then seal up somehow;
3. Dig further down through concrete to cut clay pipe down below collar, to be able to fit rubber connector round outside - not ideal as seems likely to risk more damage to clay pipe?

Any suggestions gratefully received! Thanks in advance

 

[CBW]

Carefully expose more/remove the concrete and you might be able to fit a McAlpine DC-1. If you attack the concrete further back 1st.

 

[Hugh Jaleak]

I'd expose a bit more, and ascertain condition of clayware below, including Rest Bend (if not too deep) , see what you're up against and replace as required. I would be sceptical if any mortar repair on that will last, any slight movement and it'll break again. A flexible joint is preferable.