Does this mean you think that supply is adequate and the only issue is that? We have been running a deficit of 200,000 units of housing a year for over 30 years. The shortfall has been made up, in London at least, by turning flat living rooms into bedrooms and splitting up housing into smaller and smaller units.
Also 200,000 units over 5 years is not impressive it's downright pathetic. We used to build 200,000 units of council housing a year as well as 200,000 units of private housing a year.
I don't care if a party gives away the housing as an electoral bribe down the line I just want the housing to be built now and continue to be built to keep house prices from ever going up.