Boris Johnson has visited a new 'super vaccination hub' which has opened in Bristol.
Mr Johnson was taken in and out of the stadium via the back entrance before being shown around by chief nurse Anne Morris.
He spoke with Caroline Cook, an ambulance first responder who was being given a jab, as well as Hazel and John Watson, 82 and 81 respectively, who had just received their vaccines.
He also saw Royal Navy personal from South West being taught how to give vaccine.
During the visit, the Prime Minister revealed about two million people have been vaccinated with around 2.4 million jabs across the UK.
He said around 40 per cent of all 80-year-olds have had a vaccine as well as 23 per cent of care home residents.
Mr Johnson warned tougher lockown measures may be needed if Government "feel that things are not being properly observed".
He said: "We're going to keep the rules under constant review.
"Where we have to tighten them, we will.
"We have rules in place already which, if they are properly followed, we believe can make a huge, huge difference.
"It's now that people need to focus... when they're out shopping, whether they're buying cups of coffee in the park or whatever it happens to be, they need to think about spreading the disease.
"Now is the moment for maximum vigilance, maximum observance of the rules.
"Of course, if we feel that things are not being properly observed then we may have to do more."
Mark Kelly, the managing director at Ashton Gate stadium, said the opening of the vaccination hub is a "massive milestone".
Sue Jones, 57 and from Clevedon, works for North Bristol NHS Trust and was one of the first to receive the jab at Ashton Gate.
She said: “It was amazing, actually. It was very quick and I am very pleased to have the vaccine.
“I was shielding during the first lockdown, so I am pleased to have the option today, as a retired and returned nurse.”
She said the impact of the vaccination programme would “take time” and people had to be patient.
“Everyone has still got to follow the rules of lockdown and still keep our distance from each other.”
Roslyn Wlaznik, 51, a registered care manager for a domiciliary agency, also had her jab. She said: “It was very well organised, you feel very safe while they take you through the process.
“They give you all the information that they feel you need, a bit of advice about what to do next, what to look out for.”
She said she felt “very excited” to have been offered the jab and encouraged others to have it too.
“It is very safe, it is very straightforward to go through,” she said.
“I don’t feel there’s anything to be anxious or apprehensive about.
“We work in a field where we are dealing with very vulnerable people and I think we are very lucky to be one of the first to receive the vaccine. I feel very privileged.”