Britain had no choice but to agree to bear liability if claims were made against vaccine makers as part of supply deals, officials said on Monday, adding that approval for three of the candidates procured showed their overall approach had paid off.

Prime Minister Boris Johnson has said Britain is in “a race against time” to roll out COVID-19 vaccines as deaths hit record highs and hospitals run out of oxygen.

Last month, a National Audit Office report found that Britain had offered indemnities to pharmaceutical firms as part of its agreements to procure COVID-19 vaccine candidates, ahead of regulatory approval.

Officials involved in the purchases said it was a “red line” for the manufacturers that they should be offered either statutory protection or some form of liability cover if they were to produce the vaccines for Britain.

“This was something that wasn’t a choice,” Kate Bingham, who was chair of the UK Vaccine Taskforce when Britain secured its first vaccine supply deals, told lawmakers.

“We either managed to agree some level of indemnity with the different vaccine suppliers, or we wouldn’t be securing that vaccine at all.”

Britain has agreed supply deals for seven different types of vaccine candidate, totalling 367 million doses, for at least 3.7 billion pounds ($4.93 billion).

Three vaccine candidates, developed by Pfizer and BioNTech, the University of Oxford and AstraZeneca , and Moderna, have received regulatory approval for use in Britain. The Pfizer/BioNTech and Oxford/AstraZeneca shots are being rolled out.

“If we did not make that investment, then you would not have vaccines available at the point of regulatory approval,” said Nick Elliott, former Director General of the Vaccine Taskforce.

“Looking at the overall value for money business case of the vaccines, if weighed against the cost of the pandemic, it only takes one of those vaccines to be successful to vastly recover, for the taxpayer, the investment that’s being made at risk.”