Filling hole left by removed waste pipe

[RaoulDuke00]

Hello all,

What are some ways to fill this hole in the exterior of my house?

I imagine it was left behind after a waste pipe was removed; now it's just letting the freezing air pass into the house via the kitchen from outside.

Thanks in advance,

R.

 

[oldbutnotdead]

Outside- mortar, might need bits of brick or pebbles in it just to bulk it up.
Inside stuff some loft insulation in it.
EDIT If it's a cavity wall make sure you don't push mortar into the cavity (best bet stuff the rockwool in from inside first to act as a dam)