It wasnt just the official discount. Sometimes the valuations werent kept up to date either so they were sold too cheap. I bought a three bed non block ex council flat in Brighton in 1997. The owner paid £11,500 for it from the council in 1992 and I bought it for £63,500 five years later, nearly six times the original price but the market had barely changed in that time. The subsequent owner sold it for £360,000 a couple of years ago.