Old gas meter pipe and lead pipe removal

I am looking to open up the under the stairs cupboard of a 1929 house - add flooring, plastering, storage etc as it's still like 1929 under there. There appears to be capped pipe work (copper) from an old gas fire which links to a lead pipe leading to the upstairs landing. Would a gas safe gas fitter be able to locate whether this pipe is still in use, replace and/ or take out? Is this a big job? There's also a old gas metre connection pipe coming out of the floor - iron? How can I find out if this is live? And who would be responsible for removing it? Gas board? New metre location is in the porch now and the pipes seem to run directly upstairs. Not sure when it was put in but we've been here 21 years. Any help would be greatly appreciated as it doesn't seem worth planning until the pipe work is removed.