LONDON, May 2 (Reuters) - British prompt gas prices rose on Wednesday as Norway diverted deliveries to mainland Europe at the same time as a pipeline shutdown cut flows into a domestic terminal and created supply shortfalls.
* Day-ahead gas price up 0.75 pence at 54.10 p/therm by 0806 GMT.
* Within-day contract rose 1.35 pence to 54.10 p/therm.
* Trading volumes improved following the May 1 holiday in Europe.
* The gas system was undersupplied by 3.3 million cubic metres (mcm/day), with demand forecast at 217.4 mcm compared with supplies seen at 214.1 mcm.
* Norwegian gas exports via the Langeled pipeline to Britain fell by 16 mcm/day to 44 mcm/day as the supplier rerouted some of those flows to Europe, where deliveries rose by 7 mcm/day, data showed.
* Flows into the St Fergus NSMP terminal fell to 15 mcm from 23 mcm/day on Tuesday, linked to a planned maintenance shutting down flows from Norway via the Vesterled pipeline.
* Heating demand for gas is projected to drop by 22 mcm/day with temperatures expected to climb back towards 13 degrees Celsius on average from the weekend.
* There was no concrete data yet showing any LNG tanker arrivals in Britain for May after nine cargoes discharged in April, the highest level in a year.
* The June contract slipped 0.60 pence to 52.25 p/therm.
* Day-ahead gas price at the Dutch TTF hub up 0.25 euro at 20.40 euros per megawatt-hour.
* Benchmark Dec-18 EU carbon contract down 0.01 euro at 13.29 euros per tonne. (Reporting by Oleg Vukmanovic, editing by Louise Heavens)