Liquid cargo assessment basis: use shore tank or tank outturn quantities to determine customs duty liability. Customs duty on imported liquid bulk cargo is to be assessed primarily on shore tank receipt or bonded warehouse tank outturn quantities into which cargo is pumped from the ship; where such tank receipts are unavailable and cargo is transferred to tank lorries, barges or tanks outside the Customs area, assessment may be on the ship's ullage survey at discharge. Advanced bills of entry must be amended to reflect actual received quantities, custodianship or equivalent insurance is required for shore tanks, pipeline unloading to bonded tanks requires prior permission, and supervised ullage and outturn surveys with signed reports and sampling are mandatory.