Defence Secretary Philip Hammond told lawmakers Thursday that Britain would no longer purchase F-35c variants of the Lockheed Martin Corp. fighter jet because the cost of modifications to ships needed to accommodate the plane would be about 2 billion pounds ($3.2 billion).
The jet's design — which does not include vertical take-off and landing — means aircraft carriers would need to be fitted with catapults and arrester gears.
Hammond said Britain would instead purchase F-35b jump jets, which don't require modifications to ships and are compatible with U.S., French and Italian vessels.
That option was championed by Britain's previous Labour Party government, but dumped by Cameron after he took office in 2010. At the time, Cameron said the F-35c model was "more capable, less expensive, has a longer range and carries more weapons."
"The facts have changed and therefore so too must our approach," Hammond told lawmakers. "This government will not blindly pursue projects and ignore cost growth and delays."
Work on planned modifications had already cost between 40 million pounds ($65 million) and 50 million ($81 million), and there could be further exit payments to contractors in the United States, Hammond's ministry acknowledged.
"It is as incoherent as it is ludicrous," Labour's defence spokesman, legislator Jim Murphy said. "The prime pinister's decisions have cost British time, British money, British talent and British prestige."
He said the policy reversal was a "personal humiliation for David Cameron."
Britain's defence ministry said a decision on how many F-35 jets will be purchased will be made in 2015. The country's military expects to receive its first Joint Strike Fighter jets in 2018.
Australia, Canada, Turkey, Italy, Norway, Denmark and the Netherlands are all also involved in the Joint Strike Fighter program, which has been troubled by cost hikes and delivery delays.