Abstract: An air pocket removal device is provided for the removal of residual air trapped in an underground fuel storage tank so that an accurate measurement can be made of the tank tightness and hence detect the presence of any leaks. The device is comprised of a guide column which can be fitted through the tank fuel inlet opening and which has an extendable hose fitted with a float which locates air pockets anywhere on the inner top surface of the tank. Any air present in the fuel storage can be withdrawn through the hose to the exterior.