The UK situation is in many (or at least some) ways similar to Ireland and despite BOE base rates of 4.75% there has been no collapse. It may take an external shock to Ireland to finally push the market over the edge, otherwise it may simply continue for a long period with lower or no price increases and lower levels of activity in the market. A major crash can really only happen with a major increase in unemployment and its not easy that easy for me to see that in the short term.
The thing is that the UK actually manufacture stuff that they sell to the rest of the world. They don't emply 15% of their workforce in construction. Construction doesn't account for 20% of GDP in the UK. The UK's credit bubble is about half of what ours is, on a per-person basis.