A retrievable top anchor tool for releasably locking a tubular in place in a previously installed host casing, comprising: - a central energizing mandrel disposed around a longitudinal tool axis, comprising a set of inclined surfaces distributed around a circumference about the longitudinal tool axis and facing away from the tool axis, said central energizing mandrel having a lower end, and an upper end which upper end is separated from the lower end in an upward direction along the longitudinal tool axis; - a set of anchor segments distributed around a circumference of the central energizing mandrel, each having one or more wedge surfaces facing toward the tool axis and corresponding to and engaging the inclined surfaces of the central energizing mandrel, whereby an upward directed movement of the central energizing mandrel along the longitudinal axis relative to the set of anchor segments causes a radially outward movement of the set of anchor segments and whereby a downward movement of the central energizing mandrel along the longitudinal axis relative to the set of anchor segments causes a radially inward movement of the set of anchor segments; - a central longitudinal tool bore for engaging a tool conveyance string extending in the longitudinal direction whereby the tool conveyance string is movable through the central longitudinal tool bore in longitudinal direction; and - a release mechanism; characterized in that said release mechanism comprises a lift mechanism comprising a lift device interacting with the set of anchor segments and a release sub stop, arranged within the central tool bore for engaging a release sub provided on the tool conveyance string, which release sub stop is in mechanical communication with the lift device to transmit an upwardly directed longitudinal force from the release sub to the set of anchor segments via the lift device, and in that said release mechanism further comprises one or more pre-loaded release spring members locked with a release locking mechanism, which, when the release locking mechanism is unlocked exert a retracting bias force on the central energizing mandrel in downward direction along the longitudinal axis relative to the set of anchor segments. - a central energizing mandrel disposed around a longitudinal tool axis, comprising a set of inclined surfaces distributed around a circumference about the longitudinal tool axis and facing away from the tool axis, said central energizing mandrel having a lower end, and an upper end which upper end is separated from the lower end in an upward direction along the longitudinal tool axis; - a set of anchor segments distributed around a circumference of the central energizing mandrel, each having one or more wedge surfaces facing toward the tool axis and corresponding to and engaging the inclined surfaces of the central energizing mandrel, whereby an upward directed movement of the central energizing mandrel along the longitudinal axis relative to the set of anchor segments causes a radially outward movement of the set of anchor segments and whereby a downward movement of the central energizing mandrel along the longitudinal axis relative to the set of anchor segments causes a radially inward movement of the set of anchor segments; - a central longitudinal tool bore for engaging a tool conveyance string extending in the longitudinal direction whereby the tool conveyance string is movable through the central longitudinal tool bore in longitudinal direction; and - a release mechanism; characterized in that said release mechanism comprises a lift mechanism comprising a lift device interacting with the set of anchor segments and a release sub stop, arranged within the central tool bore for engaging a release sub provided on the tool conveyance string, which release sub stop is in mechanical communication with the lift device to transmit an upwardly directed longitudinal force from the release sub to the set of anchor segments via the lift device, and in that said release mechanism further comprises one or more pre-loaded release spring members locked with a release locking mechanism, which, when the release locking mechanism is unlocked exert a retracting bias force on the central energizing mandrel in downward direction along the longitudinal axis relative to the set of anchor segments.