Sure, it's not impossible, but there's a powerful alliance of political and economic forces that will do their utmost to prevent this from happening.

I can only see three scenarios where prices fall materially:

a) big interest rate hike (I believe this caused the 89 crash)

b) massive increase in homebuilding (250k+ p/a, sustained)

c) mass emigration out of the UK.

I really doubt a) will happen, the BOE is loathe to raise rates as our household debt is 90% of GDP, twice what it was in 1990, our economy wouldn't handle it, our banks would be insolvent as they have <5% capital. Inflation would need to be double digits before the BOE's hand is forced.

b) also very unlikely. Homeowners make up the biggest voting block, a huge vested interest group. The green belt is a sacred cow. Every time the govt hints at liberalising the planning system, the mail+telegraph kick up a 'hands off our land' campaign.

c) maybe if brexit goes really badly, but we'd be in a true economic catastrophe if this happens. Probably wouldn't have a job with which to pay for cheaper housing.