of lock mandrel 12 is thereby stopped as shown in fig3 locking keys 20 are still disposed inside windows 64 of lock mandrel 12 since no prepropping of locking keys 20 has occurred this feature of the present invention is contrary to that disclosed in u s pat no 4 962 813 wherein the locking keys are prepropped into the locking annulus of the landing nipple by the action of the slidable no go ring of the lock mandrel against the locking sleeve hydraulic pressure is then applied through a control line to the scssv pressuring open the valve as described in u s pat no 4 962 813 this causes the core of running tool 10 inside lower setting sleeve 45 and not visible in fig3 to engage lower setting sleeve 45 of lock mandrel 12 which is already engaged with locking sleeve 50 by means of locking lug 46 disposed in annular recess 48 according to the present invention as shown in fig3 a leading edge 60 and or top surface 61 of pawl 28 of latch assembly 24 preferably engage upper shoulder 36 of locking annulus 22 this prevents lock mandrel 12 from rising relative to landing nipple 14 due to pressure exerted from below to a point where locking keys 20 of lock mandrel 12 are no longer aligned with locking annulus 22 with latch assembly.