British Airways and Virgin Atlantic are backing a shorter third runway at Heathrow that will initially avoid the need to move the M25 and give "the benefits of expansion as soon as possible for the UK".

The two UK flag carriers, alongside industry heavyweight Willie Walsh and ground handling giant Swissport, have thrown their weight behind proposals that could mean Heathrow loses control of its own expansion.

Hotelier and local landowner Surinder Arora, whose wealth has swelled to £1.7 billion in this weekend's Sunday Times Rich List, is proposing a phased construction of the third runway to cut costs and reduce disruption.

Proponents of his "Heathrow West" solution claim this approach offers the best guarantee that the new runway will be operational by a target date of 2035.

Heathrow also claims its in-house scheme will be operational by 2035 — though critics question whether this is realistic given the scale of its proposals.

The airport is sticking to plans that have already been agreed by parliament to build a 3,500-metre runway. Among other things, this would require diverting the M25 orbital — one of the busiest sections of motorway in Europe — under the new landing strip.