DOWNHOLE APPARATUS

Downhole apparatus comprises a body for mounting on a tubular string, the body defining an internal bore. A fluid pressure actuated valve member is movable relative to the body and a normally closed flow port is provided in the valve member. With the valve member in a first position relative to the body the port is closed, and with the valve member in a second position the port is open to permit fluid communication therethrough between the body bore and the exterior of the body. The valve member is biassed towards the first position. A fluid pressure actuated latch arrangement releasably retains the valve member in the first position, the latch arrangement being releasable on application of a predetermined cracking pressure to allow the unlatched valve member to move to the second position in response to a valve opening pressure lower than the cracking pressure. The latch is resettable to relatch the valve member on return of the valve member to the first position.