There are many makes of pushfit pipe fittings that make it a lot easer to join pipes, incluing copper pipes, e,g:
Are they safe to use on gas?
In the UK, it's not legal (quite correctly, in my view) for householders to work on gas pipework or fittings at all.
If a buildings inspector or surveyor spots pushfit fittings on gas you can expect plenty of trouble down the line... to say nothing of the risk of a pinhole leak or if there's another fire nearby that melts the fitting.
While you might save a few pounds in the short term, do you want to risk your life and that of those around you? A leaky joint in a water pipe might wreck a ceiling or a floor, the same in a gas pipe might kill you.
Head here for details of the Gas Safety scheme which holds a register of tradespeople who can do the work for you.