How to permanently remove toilet/soil pipe in concrete floor

[RickDastardly]

We have a toilet in an out-building on the side of the house that we want rid of. See picture. Has anyone done similar and has advice please?

The floor is concrete, with the tiny toilet room in the middle of the whole outbuilding. It looks like the toilet is cemented to the floor (probably replaced by the previous house wreckers who left the place in a total mess) and the drain goes into the top of a what looks like a red/brown ceramic soil pipe. The house is 1960's.

What's the best (cheap and DIY) way to approach this? I'm thinking angle grinder to cut around the base of the soil pipe, although access is difficult, maybe then cut it a bit deeper and take out some of the surrounding concrete floor too. Then plug the inside of the pipe somehow and cement over the top to level the floor. Removing the toilet itself is probably just a job for a hammer and chisel around the base I guess.

 

[blup]

People used to fill it with rags or even newspaper and pour in concrete. Maybe today, some sort of insulation.

Blup

 

[Exedon]

Once toilet pan is removed the salt glazed collar will just break off with a gentle tap (if it hasn't already snapped off)
Yes fill with concrete/sand cement but best to find other end of drain and cap there normally a inspection chamber.
Then you don't leave a convenient home for rodents.