Its been quite a while a-coming. Here in the provinces house prices never went anywhere as high as they did in the home counties or the M4 corridor but in relative terms they are now just as unaffordable. A 2 bed starter house (New/Recent build) is of the order of 10x the local average skilled worker's wage.
The point is that for 3-4 years they have been offered for humunguous prices but they aren't actually selling. Presumably pressure is building up somewhere, more and more people who desperately need to sell can't, ditto people who desperately need to buy.
The big question is what will act as the initiator to the chain reaction that prompts a run of competitive selling, if we knew that we could better anticipate it? A precipitate increase in interest rates brought about by the need to end the no longer possible to ignore consumer credit boom? An oil crisis? A falling pound?
Whatever, the instability is there, the pressure is there, AFAICS it's just whatever comes first.
DG