Bronze artwork by sculptor Barbara Hepworth stolen from park in London . Art expert says it was likely sold for scrap for just a few hundred pounds . Demand for metals has led to theft from cars , telephone boxes and war memorials . Politicians are facing pressure to increase controls on scrap metal dealers to counter theft .
Bronze artwork by sculptor Barbara Hepworth stolen from park in London . Art expert says it was likely sold for scrap for just a few hundred pounds . Demand for metals has led to thefts from railways , phone lines and war memorials . Politicians are facing calls to increase controls on scrap metal dealers to counter thefts .