LONDON—More than 1,500 looted artifacts seized by customs at Heathrow are to be returned to Afghanistan. These range from prehistoric copper tools to Islamic ceramics and marble carvings that were shipped from Pakistan. The Metropolitan police's art and antiquities squad is still holding on to pieces from three further seizures. British Museum experts on the international trade in looted artifacts believe that the pieces were excavated illicitly from archeological sites. The Foreign Office will pay for their shipment back to Kabul.