Regeneration specialist St Modwen plunged into the red during the first half of this year and announced on Monday it was halting attempts to sell residential land until the market had “stabilised.”

Shares in the group were down from 310p before the announcement to 275.5p when Building went to press on Wednesday.

The statement revealed more than £37m of writedowns on residential sites and £16.9m on its commercial sites. This led to a £20m pre-tax loss in the first half of the year, against a £65.1m pre-tax profit during the same period last year.

St Modwen’s net asset value fell by almost £20m to £448.2m in the first half.

Bill Oliver, chief executive, said: “The speed of the downturn in residential land caught everyone by surprise. It has been a collapse.’’