Heathrow’s three bridges over M25

HEATHROW has floated the idea of building three giant viaducts over the M25 as part of its third runway.

Under the plan, one bridge would be a stretch of the two-mile runway while two thinner bridges would be taxiways for planes.

The proposal was presented at an engineering conference by Phil Wilbraham, who oversaw the construction of Heathrow’s terminals 2 and 5. It is the latest idea to be put forward by the airport, which has faced previous criticism from British Airways owner IAG and Virgin Atlantic that the £17bn project is unnecessarily expensive.

Heathrow initially suggested digging a 650metre 14-lane tunnel for the M25 or building a runway that would gradually rise until it crossed the motorway on a sloping bridge – although IAG boss Willie Walsh claimed this would add an extra £2bn-£3bn to the bill.

Heathrow said its plans for the third runway have not been finalised and it will be presenting a number of options later this year as part of a public consultation.