Do I need this pipe?

[cascade]

Hi all,

First time poster after gleaning a few tips and answers from lurking on here. Currently doing a bathroom refit which is my first big DIY project that goes beyond just decorating.
Could do with some help identifying the purpose of the pipe sticking out the wall in the picture I've hopefully attached. Is it some kind of vent? I am 99% sure it connects to the soil stack at a right angle to where the toilet waste pipe currently joins. The soil stack does continue up into the roof and is vented out the top.

(More info for context if you want it)
I am hoping to move the toilet slightly, which would remove the need for a whole bunch of boxing in that was previously there. However, the soil stack is boxed in to the corner of the room and putting the toilet in the new location it will involve turning the existing junction in the soil stack (or replacing it with a new one). If I can do away with this pipe sticking out the wall then that job becomes easier.

 

[leakydave]

Toilet overflow. Often not used these days as new toilets have internal overflow.

 

[Hugh Jaleak]

As above, ref Overflow.

Be very careful if disturbing any existing joints on the Soil Stack, they won't like it, and may start to leak.

 

[Madrab]

Don't normally disagree with the pro's on here but I'd track the pipe back and make sure you know eactly what it connects to. Normally, IME, toilet overflow was plastic and not copper directed downwards like that.

That looks more like pressure safety relief pipework.

Do you have an unvented hot water cylinder?