A pressure relief comprises a valve body which includes an inlet bore that is connectable to a flow line, an outlet bore that is connectable to a vent line and a valve bore that extends to between the inlet and outlet bores. A valve member is slidably supported in the valve bore and is moveable between a closed position in which the fluid in the flow line is prevented from flowing from the inlet bore to the outlet bore and an open position in which the fluid in the flow line is permitted to flow from the inlet bore to the outlet bore. A solenoid operated pilot valve is connected to the valve body over the valve bore, and a fluid chamber is located in the pilot valve above the valve member. The fluid chamber is filled with a hydraulic fluid, and the hydraulic fluid in the fluid chamber is operatively engaged with the valve member. In a closed position of the pilot valve the hydraulic fluid is trapped in the fluid chamber to thereby prevent the valve member from moving from its closed position to its open position, and in an open position of the pilot valve the hydraulic fluid is released from the fluid chamber to thereby allow the valve member to move from its closed position to its open position.