David Cameron faces knife crime, alcoholism, an out of touch political class and a wide array of failing public services; from the NHS to plain old protect and serve coppers. Against that pleasant backdrop are self-alienated immigrants, a rising tide of British nationalism, a bickering fragile relationship with an increasingly bickering and fragile EU. The future hardly looks better. The next generation is apathetic, uneducated and largely concerned with getting the same outrageous benefits their fathers did. To top it all off there's "The Debt" (if anything deserves to be a special noun, The Debt does), an uneasy alliance with a party stealing ideas from the 1960s and a twin set of uncertain deployments in Afghanistan and Iraq.
I'm going to take a shot in the dark and say that what happens to Cameron will be, unquestionably, bad. Labour's long list of problems it never fixed during the 16 years it was in power are all, quite suddenly, rearing their ugly heads at once. Unlucky for Cameron, he won't have the ability to be preemptive; a priviliege extended to both Gordon and Blair. Instead he'll be trying to apply bandades without a parliament majority with the dual albatrosses of the Liberal Democrats and Labour fear mongering.
EDIT: Oh, and the financial crisis. Can't forget that Mt. Everest.