When Boris Johnson delayed “freedom day” on Monday, he laid out what many are describing as an ambitious new target: to vaccinate all UK adults by 19 July and to secure a double dose for two thirds of the adult population by this new unlocking date. 

Ministers had previously pledged to offer jabs to all over 18s by 31 July. So the PM’s announcement has been widely interpreted as a promise to accelerate the pace of the roll-out in the coming weeks.