Has the ignition gone on my Worcester 280 combi boiler?

It was working fine yesterday, now I have no hot water or heating. When I try to get either, the boiler sounds like it is trying to start, but can't quite get there. The pressure has been dropping very slowly.
I cannot see the pilot light - is there a chance this has gone out? And if so, how do I ignite? I cannot find a button or switch?