There had been fears that young people would not be as keen to get the vaccine, but that's certainly not the case, ITV News Political Correspondent David Wood said
Long queues were seen outside mass vaccination centres on what is dubbed 'Super Saturday', the first weekend when young adults aged 18 and over are able to get their Covid jabs.
To help young people get their jabs, several football stadiums have been converted into mass vaccination centres this weekend, including Chelsea, Charlton and West Ham football clubs.
Mayor of London, Sadiq Khan, who visited the mass vaccination centre at Stamford Bridge, said it was "fantastic" to see so many young Londoners queueing to receive the jab.
He described seeing queues "going all the way down the road, around the block, all the way to the station".
The government hopes the latest vaccination drive will help keep the virus under control and enable the country to ease restrictions further on July 19.
The increase in Delta variant cases in the UK, which now accounts for 99% of all coronavirus cases in the UK, is being driven by younger age groups.
Young people spoke of their excitement and relief as they were finally able to get their vaccines, to protect themselves and others against Covid-19.
'There's a lot of queueing outside but when I came inside, I'm excited.'
One 18-year-old, who had his jab at Stratford's Olympic Park, said he was "excited" to receive his first dose on Saturday.
He said: "There's a lot of queuing outside but when I came inside, I'm excited."
He urged others in his age group to vaccinated in order to help end the pandemic and tried to quell concerns about side effects, saying that all medicine will have side effects.
'I've been waiting a long time' to get the jab
A 21-year-old woman, who had her vaccine at Chelsea's Stamford Bridge stadium, said she was "really happy" to finally get her jab after "waiting a long time".
She told ITV News: "I feel better about going home with my parents - they've both been double vaccinated. But yeah, I'm really happy. I feel a lot safer and better."
She said that although she felt a lot of people around her age are contracting the Delta variant of the virus, she is not too concerned, knowing that most vulnerable people have already been vaccinated.
'Very grateful' to get the vaccine
Another woman who received her jab at Stamford Bridge said: "I'm pretty grateful. My entire family is vaccinated so it's nice to finally join them and feel quite safe to be able to see my grandparents and not feel like I'm going to potentially infect her. Very grateful"
'It's a relief to be able to get the second dose'
A 35-year-old man said he was "feeling really good, great" and felt relieved after getting his second dose.
Commenting on the reopening of the country once most people are vaccinated, he said: "It is good to be careful. This is a new disease, something that is still very much unknown so I'm personally pretty conservative, so happy to roll things out with caution."
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More than 33,000 cases of Delta variant, first discovered in India, were identified by Public Health England in a week. The data shows 75,953 confirmed and probable cases of the Covid-19 Delta variant have now been found in the UK.
But Dr Jenny Harries, chief executive of UK Health Security Agency, said "it is encouraging to see that hospitalisations and deaths are not rising at the same rate".
Hospital cases have also risen, though most of those needing treatment have not had a vaccine.
Surge testing amid rise in Delta variant cases
Surge testing is being rolled out in parts of south London and Cumbria due to a rise in Delta variant cases.
People living in Lambeth are encouraged to take a Covid-19 PCR test, whether or not they have symptoms. Enhanced testing began on Saturday in Clapham, Brixton, Stockwell, West Norwood and Vauxhall.
In Cumbria, everyone aged 12 to 30, who lives works or studies in the area, is encouraged to take a PCR test, whether or not they have symptoms.
So far, all confirmed cases have been told to self-isolate and their contacts have been identified, the Department of Health and Social Care (DHSC) said.
When will everyone in their 20s and 30s be vaccinated?
Everyone in their 30s taking up the vaccine offer should have their first dose by the middle of August, Health and Safety Executive (HSE) chief clinical officer Dr Colm Henry said.
There are around 710,000 people aged 30 to 39 in the UK and HSE warned this age group will take longer to complete than other groups.
For people in their 20s, everyone looking to get the jab, will have their first dose by the end of September, Dr Henry said.
With a four-week wait between doses, people in their 30s can expect to be fully vaccinated by the end of September, and those in their 20s by the end of October or early November.
More than 300,000 jabs are being administered each week but this is likely to drop to 200,000 in July, with only two supply lines available, Moderna and Pfizer.
Those vaccines are the only ones available to younger age cohorts, under advice from the National Immunisation Advisory Committee.