Robert Wiseman Dairies, the Scottish dairy producer that supplies milk to J. Sainsbury, reported pre-tax profits down 37 per cent and warned of reduced profits in the next six months due to a sharp reduction in the price of cream.

The group said profits may be reduced by up to £7m in the second half, due to weakening demand in commodity markets, and warned it may have to pass on costs to suppliers and consumers in its larger milk business.