Series 3 randomly throwing out smoke!?

Check your injector lines for damage/leaks.
Has the injector pump timing been messed with?
Is the air filter setup correctly.
Its probably something and nowt, most faults are, however if its the pump then a worn transfer pump within the injector pump is the issue.
Have you tried a compression test?

Injector lines appear fine and the injector pump hasn't been messed with. With regards to the air filter what do you mean set up correctly? I've cleaned it thoroughly and replaced with new oil. After replacing one of the injectors they all seem fine when cracked so would this rule out a problem with the injector pump? Haven't done a compression test yet. Had the lift pump out the other day and was alot of **** in it and the hand priming leaver wasn't working properly so got a new one coming tomorrow. Replaced the fuel filter a couple of weeks ago and was a worrying amount of crud in it already....

Thanks in advance

Remember the hand primer doesn't work in all cam positions, try turning the engine over a little and try again.

Thanks trax but the problem was internally within pump. Hopefully get the new one on tomorrow!