A method of metering flow through a fluid conduit which comprises a fluid obstruction means and three pressure ports (104, 106, 108) which are each coupled with pressure ports of two different DP transmitters (110, 112, 114), said method comprising the steps of: measuring a permanent pressure loss differential pressure taken between a position upstream of the fluid obstruction means and a position downstream of the fluid obstruction means; measuring a traditional differential pressure taken between the position upstream of the fluid obstruction means and an intermediate position between the upstream and downstream positions; measuring a recovered differential pressure taken between the intermediate position and the downstream position; characterized in that the method comprises the steps of: deriving a signal variation parameter for each of the three measured differential pressures; comparing each of the three derived signal variation parameters with baseline data for when the flow was dry gas and with each other; wherein, when each of the three derived signal variation parameters are compared with each other, if two of the three differential pressure measurements are identified as having a greater than expected signal variation parameter and the third differential pressure measurement is identified as having a continued relatively small signal variation parameter, then the fluid conduit pressure port (104, 106, 108) that is shared between the two DP transmitters (110, 112, 114) that measure those two differential pressure measurements is identified as being blocked; and wherein, when each of the three derived signal variation parameters are compared with baseline data for when the flow was dry gas, if all three of the differential pressure measurements are identified as having a greater than expected signal variation parameter, the fluid flow is identified as being a wet gas flow. measuring a permanent pressure loss differential pressure taken between a position upstream of the fluid obstruction means and a position downstream of the fluid obstruction means; measuring a traditional differential pressure taken between the position upstream of the fluid obstruction means and an intermediate position between the upstream and downstream positions; measuring a recovered differential pressure taken between the intermediate position and the downstream position; characterized in that the method comprises the steps of: deriving a signal variation parameter for each of the three measured differential pressures; comparing each of the three derived signal variation parameters with baseline data for when the flow was dry gas and with each other; wherein, when each of the three derived signal variation parameters are compared with each other, if two of the three differential pressure measurements are identified as having a greater than expected signal variation parameter and the third differential pressure measurement is identified as having a continued relatively small signal variation parameter, then the fluid conduit pressure port (104, 106, 108) that is shared between the two DP transmitters (110, 112, 114) that measure those two differential pressure measurements is identified as being blocked; and wherein, when each of the three derived signal variation parameters are compared with baseline data for when the flow was dry gas, if all three of the differential pressure measurements are identified as having a greater than expected signal variation parameter, the fluid flow is identified as being a wet gas flow. deriving a signal variation parameter for each of the three measured differential pressures; comparing each of the three derived signal variation parameters with baseline data for when the flow was dry gas and with each other; wherein, when each of the three derived signal variation parameters are compared with each other, if two of the three differential pressure measurements are identified as having a greater than expected signal variation parameter and the third differential pressure measurement is identified as having a continued relatively small signal variation parameter, then the fluid conduit pressure port (104, 106, 108) that is shared between the two DP transmitters (110, 112, 114) that measure those two differential pressure measurements is identified as being blocked; and wherein, when each of the three derived signal variation parameters are compared with baseline data for when the flow was dry gas, if all three of the differential pressure measurements are identified as having a greater than expected signal variation parameter, the fluid flow is identified as being a wet gas flow.