Vauxhall Vectra smoking badly, wont rev, bad miss fire.

Hi there, I was recently competing in an Autotest last weekend in my Vectra 2.2 DTi LS, Half way round one of the stages, i was in first gear at around 3.5K revs and all of a sudden there was a huge power loss, the car went down to idle and the engine management light came on. It would only rev to about 1.5K revs and was smoking badly (white smoke) the car never over heated and hasnt used any water. once the car cooled down, I restarted the engine, it took a couple of attempts whilst pumping the throttle to get it running. it starts but smokes real badly and has a really lumpy idle... it wont rev at all now. I started her up last night and when pumping the throttle, eventually it revved up once, then went back down to idle. There doesnt seam to be any smoke/steam coming from the oil filler hole or dipstick hole and also there is no deposit in the oil itself. It recently had a full service 600 miles ago. May i also add that recently, it seamed to be slightly down on power, but i think there might have been a very slight boost leak... i'll solve that once i'v solved the running issue. Thanks for any help in advance! rob.