More than 13 million people in the UK have received at least one dose of a coronavirus vaccine - part of the biggest inoculation programme the country has ever launched.

In a race against a faster-spreading variant of the virus, ministers have pinned their hopes of ending a third national lockdown on protecting the most vulnerable groups by spring.

But there are huge challenges, not least the unprecedented scale and supply demands, but also the need for rigorous safety checks and deep-freeze storage.

The government aims to offer vaccines to 15 million people - those aged 70 and over, care home residents, healthcare workers and people required to shield - by mid-February and millions more people aged 50 and over and other priority groups by spring.

These groups account for 88% of deaths so far.

The UK is now looking on track not only to offer but to deliver 15 million vaccinations by mid-February.

However, it it is not yet known how many within the top four priority groups will have been reached.

There are no figures on how many people within those groups have rejected a vaccine offer and, in addition, some regions of the UK have already begun inviting the over-60s - a group planned to be reached later in the month. Those people are also being counted in the overall tally.

What we do know is that the National Health Service (NHS) will have jabbed more than 15.5 million people by mid-February if it continues at the current rate.

The number of first doses administered each day has been steadily climbing since December - with a current seven-day average of more than 430,000.

The campaign to reach as many people as quickly as possible was boosted by a shift in policy in early January - to prioritise the first dose of a vaccine, with a second dose up to 12 weeks later, a bigger gap than originally planned.

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Overall, more than 13 million people have now received a first dose in the UK. More than 500,000 of those have received a second dose.

This progress means the UK continues to be among the countries with the highest vaccination rates globally.

The speedy rollout of the vaccine to all vulnerable people is seen as critical to reducing the pandemic's death toll and relieving pressure on the NHS.

After the first four priority groups have been offered their jabs, the programme will move on to people aged 50 and over and those with underlying health conditions.

From spring, the government plans to begin vaccinating the rest of the adult population, another 21 million people. Teachers, transport workers, supermarket workers and the military could be prioritised.

While the vaccination campaign has reached a large amount of people across the UK, there are disparities between ethnic groups and poorer and wealthier areas.

Analysis of NHS records by the OpenSAFELY group - a collaboration between Oxford University and the London School of Hygiene and Tropical Medicine - shows that black people were the least likely to have received a vaccine among those aged 80 and over, while white people were the most likely.

The study was based on more than 20 million patient records in England and covers people not living in care homes. Areas of London are under-represented in the data.

In addition, only 73% of those aged 80 and over in the poorest areas had been given the vaccine by 27 January compared with 85% in the most affluent areas.

The UK is currently receiving doses of two vaccines approved by the medicine regulator.

The Pfizer-BioNTech jab - the first to be given the green light in December - is being imported from Puurs, Belgium.

A second vaccine, from Oxford University and AstraZeneca, is being made in Britain by two biotech companies: Oxford BioMedica, based in Oxford; and Cobra Biologics, based at Keele Science Park, Staffs.

Another company, Wockhardt, based in Wrexham, fills the vials and packages them for use.

Supplies of a third vaccine to be approved, made by US company Moderna, will come from Switzerland or Spain but are not expected to be available until spring.

The UK is also lined up to receive at least three other vaccines if they are approved for use.

A jab manufactured by US firm Novavax will be made in Stockton-on-Tees in north-east England, while another by French company Valneva will be made in Livingston, West Lothian, Scotland.

The third, by Belgian firm Janssen, owned by Johnson & Johnson, should also be available later this year.

People will be vaccinated in three main ways, at:

The government has urged the public to "play their part" in supporting "the largest vaccination programme in British history", including helping people attend their appointments.

In England, more than 1,500 sites, including GPs' surgeries, community pharmacies and hospital hubs, are offering vaccination services.

They also include 90 major vaccine sites which have been set up in larger premises, such as sports centres, racecourses and showgrounds, which are capable of giving jabs to thousands of people a week.

In Wales, the vaccine is being distributed at GP practices and by mobile units. And they hope to have 35 mass vaccination centres up and running in the coming weeks.

In Scotland, as well as GPs surgeries, pharmacies and hospital hubs, there will also be a number of larger vaccination sites, including 16 in the Greater Glasgow and Clyde area.

The UK has ordered 407 million doses of seven of the most promising vaccines - three of which have so far been approved for use.

Among them are 100 million doses of the Oxford vaccine - enough to inoculate 50 million people.

This, when combined with the 40 million ordered Pfizer jabs, will cover the entire population, Health Secretary Matt Hancock has said.

The UK also has significant orders of the Moderna vaccine, which was approved in January.

But having vaccines on order is not the same as having them ready to go.

There have been a number of challenges in what is called the vaccine "supply chain" - the logistics of how the jab gets from manufacturers to people.

Getting enough supplies in the first place, checking those supplies are up to scratch and transporting vaccines according to their requirements have all thrown up difficulties.

Design by Lilly Huynh, Irene de la Torre Arenas and Sana Jasemi. Data journalism by Wesley Stephenson, Christine Jeavans and Daniel Dunford.

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