Gas pipe routing - boiler move to attic

Hi. I want to have our boiler moved from the garage to the attic. Is it ok to route the gas pipe through the house? I want to run the pipe up through the understairs cupboard then across (under the floorboards) approximately 2m to the airing cupboard and up into the loft.

I was told once by a plumber that the gas pipe would have to go up the outside of the house but I got the impression he just wanted to make the job easier. I think this option would be pretty ugly imo and from what I've seen, despite hundreds of attic installed boilers, you don't see external gas pipes often.

Thanks

yes it's ok
yes it can be done
your installer will give you a better idea

external pipework whilst not pretty is usually a lot cheaper

Great, thanks Kev. Just wanted to know my options so I can plan my garage conversion.