The military and NHS staff are on standby to roll out a Covid-19 vaccine across the UK from the start of December and will work “seven days a week”, the Health Secretary has said.

Matt Hancock said there were many hurdles to overcome before the “vast task” of vaccination could begin, including regulatory approval of the new Pfizer/BioNTech vaccine and assessment of its safety data.

But he said the NHS was leading work to get a vaccine to those most in need as soon as possible, though most people will not get a jab until 2021.

Asked whether it could be available by Christmas, Mr Hancock said that was “absolutely a possibility”, adding that vaccination clinics would be open seven days a week.

He told Sky News: “I’ve asked the NHS who are supported by the armed services in this – but the NHS very much leading this effort for deploying the vaccine – I’ve asked them to be ready from the start of December.

“And, of course, there are many hurdles that still need to be gone over and we haven’t seen the full safety data and obviously that is critical and we won’t deploy a vaccine unless we can be confident in its clinical safety.

“But we also do need to be ready should a vaccine be licensed and get through all those hurdles and ready to roll it out.”

Mr Hancock said it had always been his expectation that most people will not get a jab until 2021, with priority given to those in care homes, the elderly and health and social care staff.

“We’ve always been clear that our central expectation for the rollout of a vaccine should a vaccine come good… the central expectation of the bulk of the rollout and deployment has always been in the first part of 2021,” he said.

The Health Secretary said that once a vaccine becomes available, it will be delivered through care homes, GPs and pharmacists, as well as “go-to” vaccination centres set up in venues such as sports halls.

“We will be working across the NHS with the support of the armed forces seven days a week, over weekends, over bank holidays, to get this rolled out into people’s arms as quickly as possible,” he told BBC Breakfast.

He said the exact model would depend on which vaccine was adopted, with Oxford University and AstraZeneca expected to release results of their vaccine shortly.

“The Pfizer vaccine needs to be held at minus 70C until the last few hours before it is deployed, which obviously makes things more complicated,” Mr Hancock said.

“The AstraZeneca vaccine is a bit easier to deploy logistically.”

He said the vaccine would not be required for children and that uptake would be voluntary.

“We are not proposing to make this compulsory – not least because I think the vast majority of people are going to want to have it,” he said.

Mr Hancock urged people not to drop their guard and stop following the rules around social distancing, saying coronavirus is “still a deadly disease”.

He told Sky News he was “not going to put a date on” when life may get back to normal after Sir John Bell, regius professor of medicine at Oxford University and a member of the Government’s vaccine taskforce, said he was confident people could look forward to a return to normal life by the spring.

“This is promising news, but it is one step of many that we need to take to get out of this and to tackle this pandemic once and for all,” Mr Hancock added.

The Cabinet minister acknowledged there was “enormous complexity” in administering the Pfizer vaccine, which needs to be kept in cold storage.

“Also, you can’t take it out of that freezer more than four times on its journey from the manufacturing plant into the arm of patients… so that brings its complications,” he said.

“I’m sure that the NHS is going to rise to this challenge of deployment, and we’ve been working on it for four months now.

“What I’d say is this is a promising step, but there’s many steps still to come.”

Regarding progress on the vaccine from Oxford University and AstraZeneca, Mr Hancock said he did not know when their first data would be released.

“We’re not exactly sure when further news will come from the Oxford trial,” he said.

“But we’re working again to ensure that that can be deployed, should it come off.”

The UK Government has ordered 40 million doses of the Pfizer vaccine – enough for about a third of the UK population.

It expects 10 million of these doses to arrive in the UK before the end of this year, with people given to doses, 21 days apart.

Scientists have hailed the announcement from Pfizer and BioNTech as a significant breakthrough in the fight against coronavirus.

Stock markets rallied on the news, with the FTSE 100 jumping more than 5.5%.

Dr Richard Vautrey, chairman of the British Medical Association’s GP committee in England, said practices would “stand ready” to deliver a vaccine, with clinics potentially running from 8am-8pm, seven days a week.

In a Downing Street press conference on Monday, Prime Minister Boris Johnson welcomed news of the vaccine breakthrough but said it would be a mistake to “slacken our resolve at such a critical moment”.

He urged people to stick with the rules around coronavirus, saying there was still a long way to go.

In other developments: – Baroness Harding, the head of the Test and Trace programme, is due to be quizzed by MPs on Tuesday.

– Ofsted found some youngsters had lapsed back into nappies and forgotten how to eat with a knife and fork, while older children now lack “stamina” in reading and writing due to the pandemic.

– In Scotland, First Minister Nicola Sturgeon will announce the results of a review of the new five-tier system of measures – but said it was “highly unlikely” restrictions would be significantly eased this week.

On Monday, England’s deputy chief medical officer Professor Jonathan Van-Tam told the Downing Street press conference he was “hopeful” there would be “some vaccine by Christmas” but also urged caution.