peugeot 2.0 hdi expert (2001 model) - peugeot 2.0 hdi expert starting problems - tweeks

Hi Folks, my peugeot 2.0 hdi van will start for a second or two, but then cuts out. If you try and start it again straight away it will turn over but will not fire up, however, if you leave it for 5 minutes and try again, it will again fire up for a second or two but then cut out straight away. (I hope this makes sense?) Does anybody have any advice please??