Waste pipe leaking - help!

Firstly let me say i\\\'m a plumbing novice so forgive me if my questions are see a bit basic.

My toilet waste pipe has started leaking. The pipe is cast iron, concreted into the ground and it\\\'s leaking from a joint where the toilet attaches. We only have the single toilet going in to this waste pipe on the first floor.

Firstly can I just replace this with plastic pipe? If so are there any rules I should be aware of?

Secondly where the exiting pipe is concreted into the ground what would I expect to find if I dig it out? Does this just drop into a sewage pipe or is there likely to be some connection? Also is the sever pipe liable to be something I could break easily when digging out the concrete?

Finally is there anything I can do in the mean time to stop the leak temporarily

Thanks.

You shouldn't need to (or want to) dig up the soil pipe. The leak is from the connection from the WC to the soil pipe. It can be replaced with plastic, there are a huge variety of pan connectors available.

Your difficulty may come with sealing the plastic to cast iron. You can seal it with either a rubber gasket designed to do the job, or rapid settting cement. Both should work OK.

I don't think you'll have much luck with a temporary repair, if you do then personally I would call it permanent!