Boris Johnson has sought to reassure the public over the vaccine programme as NHS leaders privately accuse ministers of piling pressure on staff to meet unrealistic expectations amid “political boasting”. Speaking at a Downing Street press conference, the prime minister repeatedly underlined the safety of the Oxford/AstraZeneca jab, which was reaffirmed by regulators in the EU and UK on Thursday after many EU countries suspended its use. On Wednesday NHS England had announced a sharp decline in vaccine supplies for April, with ministers citing delays in millions of doses from India and the need to retest 1.7m doses. But Johnson insisted the dates in the roadmap for reopening society would not have to be moved back, saying: “Our progress along the road to freedom remains unchecked.” Meanwhile, senior health service figures told the Guardian that staff delivering the vaccines were “demoralised” and “in despair”, with ministers “constantly moving the goalposts” by briefing that immunisation targets would be brought forward, while underplaying the risk of supply disruptions. There was also “huge frustration” among family doctors running GP-led vaccination sites and bosses of hospitals managing mass vaccination centres that ministers were wrongly trying to claim credit for the success of the programme. More than 25 million Britons have received a jab since 8 December. The health secretary, Matt Hancock, conceded in the Commons on Thursday that there would be a drop-off in supply next month, saying 5m doses of the AstraZeneca vaccine would arrive later than expected from India and that a separate batch of 1.7m doses had to be retested. However, the Serum Institute of India, which is manufacturing the AstraZeneca vaccine, denied any delay and said there had been no agreed time-frame to deliver a second tranche of 5m doses, according to a source authorised to speak for the facility. The UK government declined to give any details about where the 1.7m doses being retested had originated, or why they were having to be checked for a second time. Hancock claimed the shortfall was not cause for alarm, saying: “Events like this are to be expected in a manufacturing endeavour of this complexity.” Chris Whitty, England’s chief medical officer, said there was no significant evidence that people were refusing the jab in Britain. But personnel who are centrally involved in organising the vaccination drive are annoyed about media stories promising that people of a particular age will have their first dose ahead of previous expectations and that ministers have not been open with them or the public about the risk of interruptions to vaccine supply, such as the one that emerged this week. Previously hidden tensions between the NHS and the government over the speed of the deployment and who deserves recognition have emerged in the wake of the dose shortage. The month-long slowdown has dashed government hopes of hitting the next milestone – immunising all the over-50s – well before the mid-April deadline ministers set themselves publicly. In the Commons on Thursday, Jonathan Ashworth, the shadow health secretary, gave examples of the sorts of media stories and statements that had left NHS vaccination staff irritated. “On Saturday government sources were briefing the Daily Telegraph of a ‘bumper boost’ that everyone over 40 would be offered their first vaccine by Easter. Last week the business secretary was hinting all adults could be vaccinated by June, saying ‘there’s no reason why we can’t be optimistic’,” he said. One senior NHS leader said: “There is frustration that the politicians are very focused on political boasting about the success of the vaccine rollout and who’s going to get jabbed when, without taking into account the operational complexity of what that means. “The risk is that these political boasting messages will create undue expectation over who can get their jab when, which risks overwhelming NHS staff who are already going as fast as they can. Staff are annoyed that the government seems obsessed with how things will play politically and in the media, but has no sense of the public health impact of such statements.” Another senior NHS official said: “Frontline staff want ministers to stop over-promising and be more measured and more realistic, and just stick to the original plan of which groups would be vaccinated by when – all adults by the end of July, which would still be some achievement. “Staff doing the vaccinations are demoralised and in despair about all this. They feel like they’re being set up to fail. They resent people like Matt Hancock claiming credit for the rollout when it’s the NHS that’s responsible for its success. The main barrier to speeding up the rollout is vaccine supply, which is completely outside the control of GPs and the NHS. “We are also hearing annoyance in some quarters that the successful rollout is often reported as the ‘government’s vaccine programme’ whereas the shortcomings of other programmes, such as test and trace, are readily – and not always fairly – attributed to the NHS. GPs have done a phenomenal job, showing the NHS at its very best, and that should be acknowledged.” Labour criticised the government last week for using taxpayers’ money to finance a half-hour documentary about the vaccine programme. A trailer carried the strapline: “Extraordinary. Unexpected. Fantastic. A Beacon of Hope.” Dr Richard Vautrey, chair of the British Medical Association’s GPs committee, stressed that GPs had played the key role so far and would have inoculated even more people if there had not already been several slowdowns in the availability of the vaccine. He said: “The government hasn’t administered any vaccines, they’ve commissioned NHS services to do this … The main constraint on the programme has been the amount of supplies of vaccines that the government has secured … and the restrictions the government has placed on the programme, a lot of which is to do with funding. “It’s a government programme in that it’s taxpayer funded, but we mustn’t overlook the fact that it’s the ingenuity, the energy and the commitment of NHS staff around the country that have delivered it.”