Bit concerned it might be lead but can’t make out as it’s quite rusted, and also could it be gas? We have copper hot / cold and copper heating pipes. The house is 1860s and we keep finding some very odd things. There has been refurb work done over the years (often poorly) but there’s RCD, modern boiler etc, we keep finding things “left over” with a mix of being connected / not connected. It is under the floor where above was a random platform, and the toilet placed above, leaving via 110mm waste pipe that is above standard height. Due to mould and damp of the “platform” aka the royal throne I removed it entirely, and capped the waste pipe with mcalpine cap. This is below the original floorboards.