Ford Mondeo power loss

My ford mondeo edge 2007 1.8tdci is giving me a problem. The problem is of power loss. It started yesterday while driving home from work. As I was taking off from a give way the car suddenly lost its power to pull off the give way eventually becoming worse and worse? The engine sounds ok. This morning I started the car after three attempts, drove for about 100meters and the problem started again. First it makes a jerk like movement and here the sound of the jerk and then it loses its power. Can anyone help please? Is it airlock or something to do with the gears I don’t know? The engine still kicking and sounds ok. No warning light on the dash board. I have done 51000miles with it and the was serviced by the dealer Evans Halshaw about a month go