Why is it so hard to move a runway just 12 metres?
Expansion at Gatwick Airport has moved a step closer after the government gave the plan its tentative backing.
On the surface Gatwick’s plans look relatively straightforward.
In contrast to Heathrow, which wants to bulldoze houses and reroute the M25, Gatwick is proposing to shift an already existing runway just 12 metres north, and bring it into regular use.
Yet it still may not happen for years, or may not happen at all.
How did we get here?
Gatwick officially opened as an airport in 1958. It had one runway and an additional taxi-way, that was expanded so it could be used as a back-up in case the main runway was out of action.
It was never supposed to be for daily use.
In fact, in 1979 Gatwick’s owners signed a legally binding agreement with the local council not to build another operational runway for at least 40 years.
Now, though, Gatwick is keen to increase flights in and out, especially for short-haul destinations, by putting the back-up runway into regular use.