A total of 65.6m vaccines were administered between 8 December and 1 June, including over 39.5m people with their first dose (75.2%) and over 26m with both doses (49.5%).
In England official statistics show that over 55.2m doses have been given to patients - including more than 33m first doses and 22m second doses.
Health secretary Matt Hancock hailed the 75% milestone as ‘an incredible step’, but said work to immunise the population was not yet done.
The government met its target of offering a vaccine to all patients in cohorts 1-9 identified by the Joint Committee on Vaccination and Immunisation (JCVI) by 15 April and says it remains on track to offer a first dose to all adults by the end of July. It also expects to offer vaccination with both doses by 21 June to all adults over 50.
Data from PHE’s real-world study shows that the vaccines are already having a significant impact in the UK, reducing hospitalisations and deaths, saving more than 13,200 lives and preventing at least 39,700 hospitalisations in England.
Mr Hancock said: ‘I am incredibly pleased that over three quarters of UK adults have had their first dose. This is an incredible step forward in the largest and most successful vaccination programme in our history.
‘Although we’ve come so far in less than six months since the world’s first authorised jab was given in the UK, our vital work is not done. We must redouble our efforts on the second dose to ensure as many people as possible have maximum protection.
Vaccines minister Nadhim Zahawi, said: ‘I want to pay tribute to everyone involved who has helped deliver the vaccine into arms at record speed - the NHS and care staff, volunteers, pharmacists, civil servants and more - this was truly a momentous national effort.
The government recently brought forward second vaccine appointments for over-50s and at-risk groups in an attempt to curb rising cases of the Indian variant of the virus, now referred to as 'delta'.
GP practices working across PCN areas administered their first COVID-19 vaccinations on 14 December, and have been responsible for around three quarters of all jabs - coming up with novel solutions to vaccinate their patient lists.
GP surgeries have also been praised for their work in boosting vaccine uptake among groups with high hesitancy rates, using their relationships in the community to build confidence around the jab.