Wow, fantastic news, thanks OP! Got to give TK credit, they hung in there on low loads for quite a while (I used them in 2010, both flights I took were barely a third full) so they must have seen long term potential in BHX, its a massive vote of confidence in the airport by a major international airline player
I can also highly recommend IST as a city break, a really cosmopolitan city and the souq is amazing, brilliant for spices, fabrics and trainers