International Airlines Group has welcomed the decision to expand Heathrow but at the same time has warned the government cost to customers must not increase from today’s level if the airport is to have a future.

Willie Walsh, IAG chief executive, said: “We’re pleased that a decision has finally been made but the cost of this project will make or break it.

“The government’s directive to cap customer charges at today’s level is fundamental.

“Heathrow is the world’s most expensive hub airport so it’s critical that new capacity is affordable.

“The airport has consistently argued that the British economy will benefit if the third runway is approved.

“Heathrow want it, argued for it and now must ensure it’s the UK and the travelling public who get the benefits from the runway not the airport’s owners.

“An efficiently built Heathrow will demonstrate that the UK can deliver cost effective infrastructure and compete on the world stage”.

The third runway will be funded by airlines and their customers and does not come from the public purse.

Walsh continued: “We will be vigilant in ensuring that Heathrow does not raise charges to benefit its shareholders to the detriment of the travelling public.

“We believe it’s sensible that this is properly debated and we look forward to being consulted about our views.”

IAG – which operates Vueling, Iberia and British Airways – is the biggest carrier at Heathrow.