Pilot light wont light?

I have a Baxi Bermuda boiler (old type). Left the heating on while i popped out, and when i came home the heating had gone off. i soon discoverded the pilot light had gone off. i tried to re-light it but to no avail. The fire still lights so i know i have gas supply, and i can see the igniter sparking when i press the button, but the pilot light just wont light? Please help