Container structure for removal of vacuum pressure

A hot-fill PET container or bottle 10 for filling with a liquid at an elevated temperature. The container has a side wall 9 extending to a lower portion including a pressure panel 11 and a base 2 in its unfolded or pre-fill position. The pressure panel 11 is transversely oriented and has a decoupling or hinge structure 13, an initiator portion 1 and control portion 5 of a steeply angled inverting conical section between 30 and 45 degrees. The control portion enables the inversion of the panel 11 into the container 10 to compensate for vacuum or reduced pressure induced within the container as the liquid cools down. The base 2 can also have a plurality of reinforcing ribs 3.