Majority of the falling prices in London are for leasehold flats, which most buyers now won't touch, and rightly so - service charge bills are exploitative to the extreme.
Most new-build developments in London don't sell out anymore, with developers hanging onto dozens of units post-completion of the building - this type of reality was completely unheard of 10 years ago, and the difficulties developers are having in finding buyers is meaning a lot of hesitancy in them launching future projects.
Major reform of the sector is needed.