London's Heathrow Airport in the UK has recorded the busiest year by serving close to 73.4 million passengers in 2014, an increase of 1.4%.
The airport said while it recorded a strong operational performance and highest passenger satisfaction among the European hub airports, it had seen a decline in annual operating profits by 10% to £839m.
Sky News reported that the depreciation costs associated with the airport's new terminal two resulted in the decline in operating profits.
In a statement, the airport warned that its full capacity is making the UK lag in direct flights compared with growth markets.
Heathrow Airport CEO John Holland-Kaye said: "Heathrow performed very well in 2014, with record levels of passenger service and numbers of passengers served. The successful opening of Terminal 2 means the nation now has a world-class front door and passengers rate us the best hub airport in Europe.
"But with Heathrow full, the UK is falling behind European rivals in the race for growth. An expanded hub airport is best for Britain and backed by Britain. We have made Heathrow better - now it is time to make it bigger, and connect all of Britain to global growth."
The airport is currently waiting for the recommendations of the Airports Commission on its expansion. To be released after the general elections in the country, the recommendations will decide which airport between Heathrow and Gatwick will receive the government's funding for expansion.
Image: Heathrow Airport received around 73.4 million passengers in 2014. Photo: courtesy of LHR Airports Limited.