You need a torch of some kind.

And I'd rather not have the kind of "wide mouthed plastic jug" art suggests, though something equivalent is essential. Stuck in a tent a long way to the bog and its pissing doiwn with rain, and your bladder is bursting...

But a jug sounds too like the kind someone might put beer in. A purpose made container with a good lid or something like that is better.

And a waterproof cape of course. And best a brolly as well. And a few black plastic bags.