The Covid vaccine will reach everyone in the UK who needs it - whatever the outcome of post-Brexit trade talks, the medicines regulator head has vowed.
Dr June Raine said officials had a clear "goal" and were "fully prepared for any possible outcome".
Asked about a no-deal situation, she told the BBC's Andrew Marr Show: "We have practised. We are ready."
The first jabs are being given this week and Dr Raine said people could have "real confidence" in their safety.
The EU and UK are trying to reach a trade deal before a 31 December deadline.
Dr Raine, chief executive of Medicines and Healthcare products Regulatory Agency (MHRA), said: "We are ready and we know that whatever the deal we will be able to ensure that people have access."
She said the "goal" of the MHRA was to "make sure that whatever the outcome, whatever the deal, that medicines and medical devices and vaccines reach anyone in all parts of the country in the same way without any interruption at all".
Responding to a question on the same issue, Environment Minister George Eustice told Sophy Ridge on Sky News: "We have got many contingency plans in place and there won't be any effect on the deployment of this vaccine from a no-deal Brexit."