a device for a hydraulic cutting tool for cutting of at least one pipe or tubular object beneath a water floor , wherein the cutting is carried out from a surface facility . the cutting tool is anchored in a pressure tight manner in the pipe , whereupon pressurised gas is pumped into a pipe section immediately below the cutting tool . with this , liquid , and eventually pressurised gas , will flow out of the pipe section via a short drain pipe through the cutting tool , so as to create a gas filled pipe volume comprising the relevant cutting depth in the pipe section . the invention differs from prior art by the outflowing liquid being led onwards up to the surface facility via a drain line . the upper end portion of the drain line is connected to at least one adjustable choke device . this allows the gas overpressure in said pipe volume to be controlled during the cutting , providing optimal operating conditions during the hydraulic cutting .