I beleive that govt policy is very much centered on high speed rail within UK and even in Europe so aviation is not that high on the agenda, as well as having variouse issues with Green agenda attached to it (APD good for tax raising though if you are politician). As our political masters all work out of London the Channel tunnel makes this quite logical for them and those who live in the SE. However for the rest of the country high speed rail is just not an option for the forseable future, and even when built journey times via SE England will still be longer than flying.
Do we not all remember when the tunnel was being sold to us how we were going to get Night Sleepers from the North of England / Scotland to Europe (Rolling stock now in Canada I beleive) and how we will commute Manchester to Paris via the Channel Tunnel for example. British govt,s have never had a joined up transport policy as they take too long to put together for politicians who just love to tinker, and do not return quick enough profits for UK banks so little intrest there either.
Small rant over time for G&T !