Pegasus will operate up to 55 direct flights to Turkey a week this summer, flying to five destinations – Ankara, Antalya, Dalaman, Istanbul and Izmir.

After launching from Stansted in 2007 with a single Istanbul flight, Pegasus has now carried six million passengers on routes from Stansted.

Gareth Powell, Stansted managing director, said Pegasus had built "an incredibly popular network" at the Essex airport.

"By increasing capacity and frequency on existing routes, passengers will have more choice and flexibility without having to travel to other airports," said Powell.

"We look forward to working with them for many years to come as they continue to develop and grow their services from London Stansted."

Pegasus was founded in 2005 and now operates a fleet of 93 aircraft, predominantly modern Airbus A321neos. It serves 129 destinations across Europe, the Middle East, North Africa and Asia, including 36 in Turkey.

Barbaros Kubatoglu, Pegasus chief financial officer, said reaching the six million passenger was "a special milestone" in the carrier’s history.