ERIC Curran ("No easy answers on affordable housing", Agenda, The Herald, August 8) is correct in his assessment that the housing market is complex.

Among the causes of high house prices he highlights “limited land suitable for development”.

Yet figures published in the UK Housing Review show that in every year from 2006/07 to 2016/17 the number of units given detailed planning permission by Scottish local authorities exceeded the number of houses built. We might expect year-on-year variations, or variations over an economic cycle. But something is wrong when, at the end of an 11-year period, some 39,000 planning permissions have been granted over and above housing units built.

To put it bluntly, the equivalent of two and a quarter years of housing completions have been “lost”, and this something we cannot afford.

The UK Government ordered an investigation into poor build-out rates south of the Border. The Scottish Government should do the same.

Professor Mark Stephens,

Editor, UK Housing Review, The Urban Institute,

Heriot-Watt University, Edinburgh.