Thanks Chuck for the sensible pragmatic response. Makes sense it was probably a flue pipe as it’s near a previous boiler site, but pipe itself appears to be zinc.
I will err on the side of caution and leave alone.
This pipe is coming through kitchen ceiling, presume it’s an obsolete vent pipe. I want to cut it back further into loft void. Am concerned the honeycomb seal is asbestos. Any advice as to what it was for, and would it be safe to cut...