Opening a new hub airport in the Thames estuary would force the closure of Heathrow and trigger the UK’s biggest round of job losses, the airport’s owner claims.

Creating a third runway at the west London hub would be “cheaper, quicker and better for the economy” than building a new airport from scratch.

The 76,000 people employed at the airport would face redundancy or relocation, according to research commissioned by Heathrow Airport Holdings to present to the UK aviation commission

That would be more job cuts than during the worst year of pit closures – in 1984 at 30,000 – the company said.

The report claims adding capacity at Heathrow would be better for jobs and passengers than a new hub at Stansted or in the Thames estuary – a scheme backed by London mayor Boris Johnson.

Heathrow chief executive Colin Matthews said expansion would “put Britain ahead in the global race, connecting UK business to growth more quickly and at less cost to the taxpayer than any other option for new capacity”.

Heathrow was “better located for passengers, business and jobs”, he said and it could be expanded up to seven years quicker than creating an entirely new hub.

“Why build from scratch at a new hub when we can build on the strength that already exists around Heathrow today?”