Luton Airport’s major expansion has been given the green light by ministers, who overruled advice from planners to reject the project until it met certain environmental conditions.

The approval, granted by transport secretary Heidi Alexander, means the north London hub can break ground on construction work that will see it add a new terminal and taxiways, and nearly double its annual capacity from 18m to 32m passengers.

The work, which is slated for completion by the mid-2040s, would allow it to facilitate an additional 77,000 flights a year compared with the 132,000 it hosted last year. It is also expected to create 4,200 new jobs.

Alexander has decided to push ahead with the expansion plans despite the Planning Inspectorate advising the transport minister to reject the airport’s application on environmental grounds.

The body had argued the additional capacity would impeded on the “relative tranquillity” of the nearby Chiltern Hills, a picturesque area of the home counties much of which is designated an ‘Area of Outstanding Natural Beauty’.

But a Department for Transport (DfT) statement said that “after careful consideration”, Alexander opted to ignore those recommendations and accept the airport’s development consent order (DCO).

“The secretary of state has approved Luton Airport’s application to expand its passenger capacity via the construction of a new passenger terminal and additional aircraft stands,” a DfT spokeswoman added.

In a letter addressed to the Planning Inspectorate, DfT official Gareth Leigh wrote the “secretary of state had reached a different conclusion to the [examining authority]” regarding whether the expansion’s effect on the Chilterns National Landscape should mean the expansion should be blocked.

The decision brings to and end months of delays and speculation about whether it would get the go ahead. The government had pushed back its final determination three times before today.

The move is the latest evidence of the government’s push to approve major infrastructure projects in the UK, after it gave Heathrow airport permission to apply for a third runway earlier this year. It has also indicated it will approve Gatwick’s application for a second runway once it conforms to a handful of environmental conditions.

In a landmark speech in January, Chancellor Rachel Reeves committed to changing government policy “to stop blockers getting in the way of development”. She also vowed to push through its flagship Planning and Infrastructure Bill, labelling it a “priority for this government”.