A flow stop valve positioned in a downhole tubular, particularly a flow stop valve which may be used with a dual density fluid in deep sea drilling or cementing application. The flow stop valve includes a housing and first and second receiving portions attached to first and second ends of the housing. A flow through the valve is selectively permitted between the housing and the first and second receiving portions. A valve element, such as a spindle, is slidably received in the first and second receiving portions. The valve element and housing together form a valve to selectively prevent flow through the flow stop valve. A first end face of the valve element and the first receiving portion define a first chamber and a second end face of the valve element and the second receiving portion define a second chamber.