The UK's medicines regulator has said a decision on whether to approve the Pfizer/BioNTech coronavirus vaccine will be made in the "shortest time possible", after receiving data on the drug.
The Medicines and Healthcare products Regulatory Agency (MHRA) said it will now "rigorously assess these data and the evidence submitted on the vaccine’s safety, quality and effectiveness".
"As we have received this data through a rolling review, we have already started our analysis and will aim to make a decision in the shortest time possible, without compromising the thoroughness of our review."
The companies which have produced the vaccine - US firm Pfizer and German company BioNTech - say their vaccine is 94% effective in protecting over-65s from Covid-19, with trials suggesting it works equally well in people of all ages, races and ethnicities.
The government welcomed the MHRA announcement that it was reviewing data from the vaccine - of which the UK has ordered 40 million doses, enough for 20 million people.
The majority of doses are anticipated to be deployed in the first half of next year, with the rest coming by the end of 2021.
The government has purchased seven different types of vaccine in advance and procured 355 million doses, including 100 million doses of the vaccine being developed by AstraZeneca and Oxford University, which was recently reported to be 'up to 90% effective' against Covid-19.
Clinical trials of the Pfizer/BioNTech vaccine have not reported any serious safety concerns but it will not be approved by the MHRA unless it meets their "strict standards of quality, safety, and effectiveness".
Before giving approval the MHRA says it will seek advice from the government’s independent advisory body, the Commission on Human Medicines.
It said: "The Commission will critically assess the data too before advising the UK government on the safety, quality and effectiveness of any potential vaccine.
"The safety of the public will always come first. Our job is to work to the highest standards and safety is our watchword. "
Chair of Vaccines Taskforce Kate Bingham said the UK is "moving ever closer to having the means with which to help end this pandemic".
She added: "Irrespective of the outcome, which we all hope will be positive, this is a tremendous day for science.
"It is testament to the herculean efforts of the scientific and biopharmaceutical community and it makes me immensely proud.”
The Department for Health and Social Care said the news "marks the next step forward for the vaccine following the MHRA’s confirmation that it has received the necessary data to progress their review into whether the vaccine meets the required standards".
Health Secretary Matt Hancock said: "The whole country will be cheered by the news that Pfizer/BioNTech have formally reported the data from their clinical trials for their vaccine to the regulator. This is another important step on the road to recovery."
“If approval is granted," he said, "the NHS will be ready to deliver.
"An enormous amount of work has taken place to ensure we have the logistical expertise, transport and workforce to roll out a vaccine according to clinical priority, at the speed at which it can be manufactured," he added.