A downhole tool (10,200) for cutting a casing with a first inside diameter and a casing with a second inside diameter in a wellbore, comprising: a tool body (12,212) having a through bore; a cutting mechanism (30,230) configured to cut the casing; and a gripping mechanism comprising: a cone and at least one slip; the at least one slip being configured to engage a surface of the inside diameter of casing by bearing against the cone; wherein: the cone is circumferentially disposed about a section of the downhole tool and has a cone slope wherein an angle of the cone slope is configured so that the gripping mechanism grips casing of the first and the second inside diameters; the gripping mechanism is located above the cutting mechanism when positioned in the wellbore; and the cutting mechanism comprises a plurality of knives (32,232) and a sleeve (52, 252) configured to be axially moveable within the tool body to move the knives between a storage position where the knives are retracted and do not engage the casing and an operational position where the knives are extended and engage the casing, wherein the sleeve of the cutting mechanism is configured to move in response to fluid pressure acting on at least part of the sleeve. a tool body (12,212) having a through bore; a cutting mechanism (30,230) configured to cut the casing; and a gripping mechanism comprising: a cone and at least one slip; the at least one slip being configured to engage a surface of the inside diameter of casing by bearing against the cone; wherein: the cone is circumferentially disposed about a section of the downhole tool and has a cone slope wherein an angle of the cone slope is configured so that the gripping mechanism grips casing of the first and the second inside diameters; the gripping mechanism is located above the cutting mechanism when positioned in the wellbore; and the cutting mechanism comprises a plurality of knives (32,232) and a sleeve (52, 252) configured to be axially moveable within the tool body to move the knives between a storage position where the knives are retracted and do not engage the casing and an operational position where the knives are extended and engage the casing, wherein the sleeve of the cutting mechanism is configured to move in response to fluid pressure acting on at least part of the sleeve. a cone and at least one slip; the at least one slip being configured to engage a surface of the inside diameter of casing by bearing against the cone; wherein: the cone is circumferentially disposed about a section of the downhole tool and has a cone slope wherein an angle of the cone slope is configured so that the gripping mechanism grips casing of the first and the second inside diameters; the gripping mechanism is located above the cutting mechanism when positioned in the wellbore; and the cutting mechanism comprises a plurality of knives (32,232) and a sleeve (52, 252) configured to be axially moveable within the tool body to move the knives between a storage position where the knives are retracted and do not engage the casing and an operational position where the knives are extended and engage the casing, wherein the sleeve of the cutting mechanism is configured to move in response to fluid pressure acting on at least part of the sleeve. the cone is circumferentially disposed about a section of the downhole tool and has a cone slope wherein an angle of the cone slope is configured so that the gripping mechanism grips casing of the first and the second inside diameters; the gripping mechanism is located above the cutting mechanism when positioned in the wellbore; and the cutting mechanism comprises a plurality of knives (32,232) and a sleeve (52, 252) configured to be axially moveable within the tool body to move the knives between a storage position where the knives are retracted and do not engage the casing and an operational position where the knives are extended and engage the casing, wherein the sleeve of the cutting mechanism is configured to move in response to fluid pressure acting on at least part of the sleeve.