The British government has terminated a supply deal for a potential Covid jab being developed by French-Austrian biotech laboratory Valneva, the firm said on Monday.
Britain had ordered 100 million doses of the vaccine for 2021-2022 -- the only order so far for Valneva, which has a production facility in Scotland.
Valneva said in a statement it "strenuously denies" allegations from Britain that it breached its obligations under the deal.
Prime Minister Boris Johnson's spokesman did not comment on the specifics of the company's claim but pointed out that Valneva's vaccine candidate was not yet approved.
"The comments from the company won't have any impact on our vaccine supply and did not form any part of our vaccine rollout in autumn and winter," he said.
Unlike most high-profile coronavirus shots, which use various methods to prime the immune system to fight the coronavirus, Valneva's VLA2001 is based on an "inactivated" version of the coronavirus itself.
The laboratory had said Phase 1 and 2 trials suggested its vaccine would be more than 80 percent effective.
Valneva confirmed on Monday it had received a "termination notice" despite having "worked tirelessly" on its UK collaboration.
"Valneva continues to be committed to the development of VLA2001," the firm said, adding that it would ramp up its work with other potential customers.
- 'Clearly concerning' -
Valneva reiterated that its Phase 3 results should be available early in the fourth quarter.
The results would be used as part of its submission for approval to the UK's Medicines and Healthcare products Regulatory Agency (MHRA).
"Subject to these data and MHRA approval, Valneva believes that initial approval for VLA2001 could be granted in late 2021," the firm said.
Scotland's health minister Humza Yousaf said on Twitter that the decision to terminate the contract was "clearly concerning" for the workforce near the firm's plant in Livingston, just north of Edinburgh.
"We will work with the Company to seek assurances about the future of the facility," Yousaf said, adding that the government still had plenty of jabs for its vaccination programme.
Prior to the announcement, the UK government had ordered more than 535 million doses of vaccines from various companies.
The vaccine made by UK-Swedish drugs giant AstraZeneca is the most widely offered in the UK, though under-40s are offered jabs made by Pfizer and Moderna because of concerns over side effects with AstraZeneca.