At Marine Corps Air Station Beaufort in South Carolina, both British and American pilots are learning how to fly the F-35B. (Jeff Martin/Staff) Jeff Martin

WASHINGTON — The United Kingdom’s first four F-35 fighter jets arrived at RAF Marham on Wednesday night, a major milestone that paves the way for the Royal Air Force and Royal Navy to get ready to declare the jets operational later this year.

The four F-35Bs took off from Marine Corps Air Station Beaufort in South Carolina earlier that morning. The jets, which were flown by British pilots from 617 Squadron and refueled by the Airbus A330 Multi Role Tanker Transport, landed in Marham at about 8:15 p.m. local time.

The British jets are arriving at Marham two months ahead of schedule, which will allow pilots more time for training as they prepare for an initial operational capability declaration later this year.

“These formidable fighters are a national statement of our intent to protect ourselves and our allies from intensifying threats across the world,” U.K. Defence Secretary Gavin Williamson said in a statement.

“With a game-changing ability to collect crucial intelligence, fight wars and tackle terrorism, these are the most advanced jets in British history. The work that’s gone into their early arrival shows they have the people to match,” he said.

Britain has already spent about $736 million to get RAF Marham ready to accommodate the new jets, with investments including resurfacing runways and buying new landing pads so that pilots could practice vertical landings.

Britain has indicated it will buy as many as 138 F-35s. It has committed to an order of 48 F-35s, and Lockheed Martin has already delivered 15 of those jets.

As a partner of the F-35 program, the U.K. has had to help shoulder development costs but has also received industrial kickbacks to domestic defense companies. More than 500 British companies are involved in the construction of the F-35, said Lockheed Martin, which estimates that those firms have made about $13 billion in contracts.

This May, Defense News traveled to MCAS Beaufort, where the U.K. has about 150 personnel training alongside U.S. Marines. There, U.S. and British pilots undergo the same curriculum, train together and regularly swap jets.

Once F-35s start arriving at Marham, those pilots will be able to begin practicing U.K.-specific tactics, which are not taught at Beaufort, where basic training takes place, Wing Cmdr. Scott “Mox” Williams, the U.K.’s senior national representative at Beaufort, told Defense News on May 17.

“Having that six months is great to kind of ramp up the U.K. tactics rather than if you were to wait and do it all in July,” he said. “That would only give us four months to do that work-up, which is tight.”

Pilots will also be able to get comfortable flying in local airspace and will train with other U.K. aircraft like the Eurofighter Typhoon and the Panavia Tornado, he said.

While the Ministry of Defence hasn’t laid out its parameters for initial operational capability, Williams said it will involve having a certain number of planes ready to conduct day or night missions in the areas of air interdiction, close-air support, suppression of enemy air defenses, defensive counter air and offensive counter air.