Gas hob ignition

Question

Please can someone suggest a solution: My gas hob has an electric ignition switch. I ran out of LPG, refilled it, and now the switch doesn't spark/click. It was going perfectly before running out of gas (it was definitely empty as I was cooking at the time). The electrics are fine as I tested with an extension cord.it seems strange that the ignition should break at the same time as gas runs out. It's only 3 years old. Any suggestions very welcome, thanks....