An end effector assembly for an electrosurgical instrument comprises a pair of opposing first and second jaw members. At least one of the jaw members is movable relative to the other between a first open position in which the jaw members are disposed in a spaced relation relative to one another, and a second closed position in which the jaw members cooperate to grasp tissue therebetween. The first jaw member comprises first and second sealing members extending along a length of the jaw and being separated by an insulating member therebetween, and is provided with an electrically-conductive cutting electrode supported on the insulting member. The second jaw member comprises third and fourth sealing members extending along the jaw and being separated by a recess therebetween, an electrically-insulating anvil being located in the recess opposite the cutting electrode. The electrically-insulating anvil is located on a support member attached to one or both of the third and fourth sealing members, and the anvil and support member are such that the anvil is spring mounted with respect to the third and fourth sealing members and such that the anvil can move within the recess by at least 0.5 mm when tissue is grasped between the jaws of the end effector assembly.