Any plans for airlines to expand at BHX will be on hold while the oil price is over $100/barrel.
for example
United scraps expansion plans because of oil - Travel - News - msnbc.com
It is very likely that oil will never drop below $100/b again. If so most of the effort will be in keeping existing routes load factors up and triming timetables. I cannot see that the business case for expanding the runway could work at the current oil price. Just divide the cost by the like number of extra pax and you will get a large cost for each added pax. With BAA split up you have lots of London airports fighting for traffic.