French vaccine maker Valneva says the UK government has scrapped a deal for its Covid-19 vaccine.
The UK had about 100 million doses on order, after it increased its request by 40 million in February.
The firm said that the UK government served notice over allegations of a breach of the agreement, which it "strenuously denies".
The government said the decision would have no impact on vaccine supply in the UK.
"The comments from the company will not have any impact on our vaccine supply and did not form any part of our vaccine rollout in autumn and winter," a spokesperson for Prime Minister Boris Johnson said.
The UK's Medicines and Healthcare products Regulatory Agency (MHRA) has not yet approved the Valneva vaccine.
In a statement on its website, Valneva said: "Valneva SE, a specialty vaccine company, today announced that it has received a termination notice from the UK Government (HMG) in relation to the Supply Agreement for its Covid-19 vaccine candidate, VLA2001.
"The contract provides HMG with the right to terminate. HMG has alleged that the company is in breach of its obligations under the supply agreement, but the company strenuously denies this."
The firm said on Monday that results from its phase three trials were due later this year.
It added: "Valneva has worked tirelessly, and to its best efforts, on the collaboration with HMG including investing significant resources and effort to respond to HMG's requests for variant-derived vaccines."
The company hopes that, dependent on the results of its continuing trials and sign-off from the UK's MHRA, initial approval could still be granted in 2021.
Its vaccine is expected to be given as two doses and contains a dead version of coronavirus that cannot cause disease, but should teach the body's immune system how to fight it.
