...Or you can try this... If you can wiggle the post and see any movement of the concrete block, have the availability of a towing chain (not a strap, they stretch too much) and a good quality car jack, place the car jack near the base of the post (obviously not on the concrete pad), link the chain (here in the U.S., we call it a log chain, since it has a hook on the end for such securing) around the base of the post near where it enters the concrete, link the other end securely to the 'lip' part of the jack and simply pull it out straight up. You may have to put the base of the car jack on a board if the ground is soft. Surprisingly, most posts come out reasonably easy using this method.
Alternately, if you can get a vehicle near the post, rather than trying to pull it horizontally (I agree, you'll damage the vehicle) place the chain as described above, then find a sturdy board or better yet another post half the length of the one you want to remove. Lean the board or post towards the post to be removed (about 40 degree angle) run the chain over the top of it and then secure it to the vehicle. Slowly move the vehicle (our ranch pickup truck works fine) tightening the chain. As you move the vehicle further, the angled post begins to straighten upwards and voila the concereted post seemingly jumps out of the ground... This is difficult to create a word picture for, but hopefully you get the picture.
We use the tractor to pull larger posts, but use the same process.