A subsea well safing method and apparatus adapted to secure a subsea well in the event of a perceived blowout in a manner to mitigate the environmental damage and the physical damage to the subsea wellhead equipment to promote the ability to reconnect and recover control of the well. The safing assembly is adapted to connect the marine riser to the BOP stack. Pursuant to a safing sequence, the well tubular is secured in the upper and lower safing assemblies and the tubular is then sheared between the locations at which it has been secured. Subsequently, an ejection device is actuated to physically separate the upper safing assembly and connected marine riser from the lower safing assembly that is connected to the BOP stack.