The boss of Heathrow today said Chinese and South American airlines were being turned away from routes into London because the world's busiest airport was full to capacity.
Colin Matthews, chief executive of airports operator BAA, said: "We have airlines come to us from South America and China to ask to fly to the UK, and we have to respond, 'only if you can find a slot to buy' which they find very difficult.
"That's why slots have traded for £25 million. We are at the limit of the number of take offs and landings at Heathrow. It is frustrating, and it is urgent," Matthews added.
His comments came as Heathrow's record traffic in 2011 - 87.4 million passengers - helped BAA (SP) Limited, which owns both it and Stansted airport, to post an underlying profit of £1.1 billion, up 17% on the previous year.
When taking into account the interest payments BAA made due to the structure of Spanish group Ferrovial's takeover of the business in 2006, the company lost £255.8 million before tax in 2011.
Matthews said that Heathrow was ready for the London Olympics this summer.
Around 80% of total Games traffic will travel through the airport, including 137,000 people - 10,000 more than have ever been inside the airport on a single day - on the day after the closing ceremony.
"We're always going to be worrying and practising," he said.
"We want to put on a welcome Britain can be proud of."
