There should be a complete stop to airport expansion in the UK. We need better airports, not bigger ones.
Economically, that is suicide.
Imagine, if American wanted to launch a new service from say, Phoenix to Europe, and naturally, LHR is the airport of choice but because of a new laws in the UK stating all airports cannot expand, they have to fly to BRU instead meaning less money coming into the UK with all those people on board ready to spend their money.
In a mixed market it is not possible to let airports refrain from growing at all. You can look at places such as Stansted who have had limits on the number of passengers but these have been limits set ahead of their current passenger numbers, well...when it was first introduced. It is like a dictatorship saying that an airport cannot do anything until they are improved - what right do the government have to tell business how to run unless it becomes a social cost that affects the government?
This is one of the reasons why the EU has not included aviation in the carbon trading scheme. If somebody was flying from Kuala Lumpar to New York. Their intention would be to fly KUL-LHR-JFK with BA but because they now have huge fees on pollution permits it is more cheaper to fly via DXB or DOH which again, takes business away from the UK and Europe. It also makes it less attractive for foreign airlines to fly into the EU.
We are in a global market and we need to keep up and in some cases stay ahead of the rest of the world.