From Longman Dictionary of Contemporary Englishgasmangas‧man /ˈɡæsmæn/ noun (plural gasmen /-men/) [countable] British English informal DHTPGsomeone whose job is to come to your home to see how much gas you have used or to repair your gas system
Examples from the Corpus
gasman• The gasman had told us it would blow up and had stuck on a waning sign to remind us. 