If Heathrow is expanded, as outlined in the Davies Commission, it would involve roadworks on the M25.

Due to overlapping, an underground section would be required for the motorway to dip under the runway.

London's mayor Boris Johnson - who incidentally favours an airport on the Thames Estuary - has suggested this could take around five years to achieve.

This has been met with a negative response from many driving authorities in the UK, as closing or restricting traffic on the six-lane motorway could prove a problem.

Speaking to the London Evening Standard, an AA spokesperson said: "The M25 is the artery on which millions of commuters and businesses rely. Any suggestion of large-scale disruption there will cause major backlash."

Similar sentiments were expressed by the RAC and the Institute of Advanced Motorists. As an important road link in London, the knock-on effects of delays could prove difficult to solve.

Of course, the other options in the Davies Commission include not expanding Heathrow at all, in favour of Gatwick, or lengthening one of the existing runways, which may not interfere with the M25 at all.