All modern fires have safety cut off valves built into them.Does the fire usually light a pilot first,then you hold the button in for 30 secs before turning it to full.If so try and light the pilot with a spill.If the gas does light check the flame is blue in colour,if it is burning yellow the air intake hole just below the pilot will be linted up.Get a piece of tube and blow through the hole and you should find it ok after.
Tony S
September 2008