Annual physical checkups in the UK

So, someone on my f-list was wondering how you even TELL if you're basically healthy in the first place. I suggested that she go to her primary care physician, and have an annual checkup, Pap smear, and the rest of it.

She's in London, so she's on NHS. But she says that annual checkups aren't covered, and that NHS basically only covers critical care and not preventative care.

That can't be true, can it? So how do you go about getting an annual physical?