This will cripple everyone who has bought since 1995 or so with negative equity... How is that possibly a good thing? If we're looking at average house prices of 3x the average income, the average house price has to drop by over £100k... We're talking a 60-70% reduction in value, that's not just going to impact people who bought at the top of the boom, that's going to impact everyone massively. It's an absolutely insane and ludicrous policy that can only have been concieved by a complete halfwit as a good idea to do now, it's at least 10 years too late to have positive effects.
I very much doubt it's going to put negative equity on anyone from 1995 onwards. I think a more realistic figure would be 2003 area maybe at 2002, as prices in 1995 were still at a low level and even in 2000 there were still low ish. And when you take into account people would have already paid a proportion of the mortgage off.