Recently purchased a mondeo mk3 on 108k miles 2.0 ttdci. Seller said that it needs a sensor or something near the turbo can't exactly remember what he called it anyway. 

When i start it on the morning I always sit in it and let it idle for a good ten minutes to let the oil warm up. At this point the engine idles fine.when I drive it for a bit and then come to set of traffic lights or something I can feel the shake and engine sounds like it's revving but it's not. Sometimes when driving coil light flickers and engine doesn't respond normally until switched off then back on. Last few days I get the coil light and engine cuts itself off and have to start it myself.

Any ideas what the problems could be or what I should look at first the cheapest option. 

I think you need to get a code reader and see jf you hve any codes come up 

Camshaft sensor is an easy change and cheap

Cheers for the info guys. I'll get myself a code reader and see what comes up. I don't know much about cars but from what I've just read about the cam sensor does seem to be the actual symptoms I'm experiencing. I have notice today on the way to work and back if I drive steadily keeping it under 2 k revs seems to run fine but still get the jerkin when coming to stop but no coil light or engine stall.

I had very similar symptoms on my Mondeo too. A new cam sensor plus a fuel filter change did the job perfectly. Less than thirty minutes to do and by far the cheapest option.