THE boss of the firm which owns British Airways has threatened to reduce its flights at Gatwick if the airport is given permission to expand.

Willie Walsh, chief executive of International Airlines Group, warned that the cost of building a second runway would result in charges that are too high.

He said: "We struggle to see any business case for the expansion of Gatwick and will consider our position at the airport if the Government backs expansion there, principally because the cost of that expansion when translated into airport charges would likely wipe out the profit we make."

Mr Walsh said expanding Gatwick could lead to a doubling of airline charges, from £7 per passenger to £14.

He added: "I don't make £7 a passenger so I'm not going to pay an extra £7. Why should airlines pay this?"

He warned that if Gatwick tried to increase landing charges to pay for the expansion, he would look to move flights to rival airport, Stansted.

Speaking at the travel organisation Abta's annual Westminster conference, he said: We will consider our position at Gatwick if there is a decision for it to expand. The cost of expansion at Gatwick would wipe out any profit we make there.

"We will definitely look to move flights to Stansted, if Stansted is cheaper. We would not be alone, a number of other airlines would look at doing this."

Mr Walsh has been a critic of expansion at Gatwick for a number of years.

However, his latest comments will be greatly concerning for Gatwick bosses who are trying to convince the Government to back them for expansion over Heathrow.

Gatwick bosses have set a £15 limit for passenger charges from the opening of the new runway in 2025 through to 2050.

They have said this limit is linked to inflation adding that they hope it would end up being much lower.

Mr Walsh was also outspoken over Heathrow's bid and warned that their proposal should be carefully looked at.

He said Heathrow's £17.6 billion proposal includes just £182 million for the actual runway, compared to £800 million for a new car park.

"My strong belief is that you cannot trust Heathrow to deliver anything in a cost-effective manner," he told the audience.

"Customers have been ripped off by Heathrow for years and leopards don't change their spots."

Mr Walsh insisted that Heathrow's shareholders must "shoulder the risk" of expansion because there is "no justification for airlines to pre-fund new infrastructure".

He added: "Today's customers should not be expected to pay for a runway that will not be operational for another 10 years.

"In many industries where passengers pay upfront to grow a business they get discounts. This would be the complete opposite. Higher costs mean higher ticket prices."

In July last year the Airport Commission recommended that a third runway at Heathrow should be built.

But in December the Department for Transport announced that the decision on which project to support would be delayed until further work on noise, pollution and compensation is carried out.