Worcester 240 combi not igniting ?

I have a Wocester 240 Combi and when I go to switch it on nothing is happening, I can normally hear the ignition clicking and it then it fires up and away to go.

I can not however hear the clicking noise, its silent, its not firing, no flames?

Ive pressed the reset button and checked the pressure gauge, and still nothing?

Any help would be appreciated. Thanks