You MIGHT be able to use your passport for foreign travel. (As you state, the pages aren't always checked thoroughly). However, I agree with others here. You be MAD to attempt to use it! You could spend a great deal of money on a trip abroad, only to be refused entry into the country you want to visit. No holiday insurance covers this sort of thing, so your holiday plans will be ruined, you'll already be hundreds (or possibly thousands of pounds) out of pocket and you'll then have to pay for an immediate return flight home. (If the only seats available are first class at, say, �3000 for the flight, you'll either have to pay this or spend time locked up in a detention centre). A new passport seems to be a much better option!
Lastly, whatever you do, don't rip a page out of your passport. The immigration authorities will assume that the page contained something like an 'undesirable alien' stamp and you'll almost certainly be held, in very unpleasant circumstances, for many hours.
Chris