Low-cost airline Ryanair has reached a long-term agreement with the new owner of Stansted Airport which will see the Irish-based carrier boost its passenger numbers at the airport by nearly two-thirds.

Under the 10-year deal with Manchester Airports Group (MAG), which acquired Stansted from the former BAA group earlier this year, Raynair will increase the number of passengers it serves at the airport from just over 13million a year to more than 18m by 2018 and to nearly 21m by 2023.

Ryanair is already Stansted’s largest airline, serving more than 140 destinations during the past 12 months, and is to add four new routes for summer 2014, to Portuguese capital Lisbon, Bordeaux in France, Dortmund in Germany and Rabat in Morocco.

Ken O’Toole, MAG’s chief commercial officer, said: “The new long term agreement between Ryanair and MAG at Stansted shows that competition really does work, and it represents great news for both passengers and UK businesses.

“The deal secures a new and exciting era for both Ryanair and Stansted, and we’re delighted to be supporting the airline’s growth over the next 10 years.

“We acquired Stansted in February this year believing we could significantly expand the services on offer by competing more effectively to make the most of the airport’s untapped potential and spare capacity.

“We were confident Stansted would grow if we offered great value to airlines, increased passenger choice and better services and facilities.

“Today’s announcement, coupled with our £80m investment in the terminal, confirms that Ryanair shares our confidence, and shows how we are succeeding in transforming Stansted under new ownership. Stansted has a really bright future in providing international connectivity for the UK.

“Over the next five years, M.A.G wants to make Stansted the best airport in London so we will continue to compete hard to win business from airlines in our drive for passenger growth and to provide customers with even more choice.”

Ryanair chief executive Michael O’Leary, a long-standing critic of BAA during its ownership of Stansted, said: “Ryanair is pleased to have agreed a new 10 year growth deal at London Stansted with MAG.

“This deal will see our Stansted traffic grow by over 50%, from 13.2m in 2012 to over 20m, in return for lower costs and more efficient facilities at Stansted.

“This agreement proves how UK airports can flourish when released from the dead hand of the BAA monopoly and is the first dramatic initiative by MAG to reverse seven years of decline, during which Stansted’s traffic fell from 23.8m to 17.5m.”

Mr O’Leary added: “As Stansted’s biggest airline, Ryanair looks forward to a decade of growing traffic, routes and jobs at Stansted.”