The business secretary has been unable to confirm, when asked a number of times, whether the UK's exit from the EU will affect supply of a coronavirus vaccine, when one is available.
When asked if he could "categorically" say Brexit disruption would not impact vaccine supply, Alok Sharma did not give a direct answer.
He said: "You've talked about vaccines but supply chains obviously is an issue across many sectors."
Mr Sharma added how the government has invested "hundreds of millions of pounds" in border infrastructure in grants "for customs intermediaries".
"It's why we are making a very big effort to communicate with businesses to make sure that they are ready, so that they can get customs clearances done.
"All of that work is ongoing. If we all get prepared, we will be in absolutely the right place post-transition."
The business secretary was answering questions at a Downing Street press conference after news this week of a successful vaccine trial which was found to be 90% effective.
Professor Stephen Powis, the medical director for NHS England, who was speaking alongside Mr Sharma, insisted the NHS will be ready to deliver a vaccine when one is available.
"We are working incredibly hard and I am confident that the NHS will be up to what will be a huge logistical challenge. We have for flu every year, we will be able to do it for Covid," Prof Powis said.
He stressed that despite positive vaccine news it was "vital" to continue to follow the 'hands, face and space' guidance - and urged everyone with symptoms to get tested.
"Both these measures will slow the growth in infections that will inevitably lead to increased hospital admissions and sadly increased deaths.
"There is hope on the horizon with a vaccine, and of course that is welcome news, but the vaccine is not here yet and it will not help us in this second wave if infections continue to rise."
He said he believes vaccine uptake in the UK will be high, with Britain having some of the highest vaccination rates in the world," he said.
Asked whether it should be compulsory, Prof Powis said: "I'm confident that the British people will want to be vaccinated, that they will understand the benefits, not just for themselves but for everybody because it's by vaccinating, by getting high rates of vaccination, that we all protect each other."
Also at the press conference Mr Sharma faced several questions on the resignation of Boris Johnson's director of communications, Lee Cain.
The spin doctor announced he would be stepping down at the end of the year after an apparent power struggle inside Number 10.
Mr Sharma played down accusations that the resignation could have distracted ministers from the task of tackling coronavirus.
"I can tell you that all of us in government are focused on one thing, which is protecting lives and protecting livelihoods."
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