Abstract: In the process of suspending a subsea hydrocarbon well (1) after finalizing the completion operation and prior to stimulation of the well and putting the well on production, preinstalled upper and lower glass plugs (11, 12) are used as temporary barriers in the tubing. The plugs allow various tests to be performed before the lower plug (12), below the production packer (10), is broken; the upper plug (11) located above the downhole safety valve (13) then forms one of the barriers required to suspend the well whilst the Blow Out Preventer (BOP) is removed and Xmas tree installed, at which point the upper plug (11) is broken.