Batches of the coronavirus vaccine have been pictured arriving at a hospital in south London ahead of the UK-wide rollout of the treatment this week.
Staff have been unloading doses of the Pfizer/BioNTech jab from boxes at Croydon University Hospital before placing them in freezers on the site.
The COVID-19 vaccine must be stored in temperatures of -70C to -80C.
Louise Coughlan, joint chief pharmacist at Croydon Health Services, said: “This is just so exciting, it’s a momentous occasion.
“The NHS has been planning ostensibly to deliver the largest vaccination programme in our history – so it’s really exciting.”
She added: “To know that (the vaccines are here) and we are amongst the first in the country to actually receive the vaccine, and therefore the first in the world, is just amazing – I’m so proud.”
Vaccinations will be administered at dozens of hospital hubs from Tuesday.
People aged 80 and over, care home workers, and NHS workers at the highest risk will be the first to receive the jab.
There are 50 hubs in the first wave of the vaccination programme in England, with more hospitals starting to vaccinate over the coming weeks and months as the programme ramps up.
The NHS’s medical director in England has said the start of the vaccination programme this week feels like the beginning of the end”.
Professor Stephen Powis said: “As a doctor, this is a really exciting moment.”
But he warned that what he describes as the “largest scale vaccination campaign in our country’s history” will be a “marathon, not a sprint”.
He said: “It will take many months for us to vaccinate everybody who needs vaccination.”
Professor Powis also admitted there were “huge complexities” but said the NHS had a “strong record of delivering large-scale vaccination programmes”.
He continued: “Hardworking staff will once again rise to the challenge to protect the most vulnerable people from this awful disease.”
Professor Powis said extra staff were being drafted in to help with the immunisation programme, and urged people to continue seeking treatment for non-coronavirus health problems.
NHS Providers, the association of foundation trusts and trusts, has told Sky News the UK could have up to four million vaccine doses by the end of the year.
GP surgeries in England have been told to start staffing COVID-19 vaccination centres by 14 December.
Health Secretary Matt Hancock has reportedly been referring to Tuesday as “V-Day” and told The Sunday Telegraph that he “can’t wait” to scrap the three-tier system of coronavirus restrictions and “get back to living by mutual respect and personal responsibility, not laws set in parliament”.
When asked if the distribution of the vaccine beginning this week could mean restrictions end sooner, he said: “Yes, it will.”
He added: “There’s no doubt that having the vaccine early… will bring forward the moment when we can get rid of these blasted restrictions but until then we have got to follow them.”