I worked for Transco (as was) a few years back. You will have to get in touch with the distribution company for your area (whereabouts are you?) that'll be National grid, Northern Gas Networks/UU Scottish and Southern, and a couple of others that I don't recall. You're looking to deal with "connections" or meter installation. Do any or your neighbours have mains gas? Is there a small, strange gassy smelling, brick building within a mile or so of your house? Are there mains replacement scars in the tarmac outside? If not you're probably out of luck.
Providing a connection to a low pressure distribution line is easy, most of the mains are PE plastic now and a Tee is welded onto the live line and run up your garden. This can be done on medium pressure lines too in some cases, but is more expensive IIRC.