LONDON — Britain’s defense secretary has committed to a deal to acquire a new fleet of Boeing-built extended-range Chinook helicopters.

Fourteen CH-47-ER Chinooks, destined principally for use by British special forces, will be delivered to the Royal Air Force under the terms of the deal signed between the British and U.S. governments.

Defense Secretary Grant Shapps on Thursday confirmed the procurement, known as the Chinook Capability Sustainment Program, will advance.

The defense ministry originally confirmed the deal in May 2021, but talks to complete the negotiations were slowed by British concerns about cost growth and other issues.

The British set the baseline budget for the program at £1.5 billion (U.S. $1.9 billion) but inflation, foreign exchange and other problems increased costs.

At one point during the negotiations last year, then-defense secretary Ben Wallace was widely reported in the U.K. to have threatened to cancel the program due to spiraling costs.

Giving evidence to the Parliamentary defense committee in November, Shapps said he too had raised the issue of axing the procurement with U.S. officials.

“We have to weigh up the cost of exiting a contract as well as going into one,” he told the committee. “I have discussed the issue with [U.S. Defense Secretary] Lloyd Austin.”

Procurement minister James Cartlidge told Parliament last year Britain’s weakening exchange rate against the U.S. dollar alone had cost the program £37 million as of Sept. 11, 2023.

In a statement Thursday, the defense ministry said negotiations with the U.S. government had produced a cost reduction.

“The U.K. has reduced costs for elements of the program by more than £300 million, ensuring value for money whilst providing our armed forces with a cutting-edge heavy lift capability,” the ministry said, though it did not release the total cost of the program or details about the reductions.

The current delivery schedule has not been made public, although a website operated by the Defence Equipment & Support arm of the defense ministry says the first delivery is set for 2027 with a manufacturing program end of 2029.

The new airframes will replace the most obsolescent Chinooks in an Royal Air Force fleet that is currently shrinking CH-47 numbers from 60 helicopters to 51. The 14 oldest Chinooks will be retired from the U.K. fleet as the new machines enter service.

No decision has yet been made on what will happen to the Chinooks when they are pensioned off .

The overall size of the British Chinook fleet will remain at 51 aircraft as the new aircraft are delivered and the oldest aircraft are retired.

The extended-range helicopter will have double the range of standard CH-47s operated by the Royal Air Force and help fill a special forces capability gap created by the early retirement of Lockheed Martin-made Hercules C-130s last year.

In a statement, Boeing said it looks forward to delivering the helicopters.

The extended-range Chinook buy is the second major British helicopter procurement to advance recently.

In late February, the defense ministry triggered the start of a near £1.2 billion competition to replace Puma and some smaller helicopters in what is known as the New Medium Helicopter program. Airbus, Leonardo and Lockheed Martin are all expected to respond.