Fewer than one in five of the British public believe the time is right to consider reopening schools, restaurants, pubs and stadiums. The findings, in a new poll for the Observer, suggest Boris Johnson will struggle to convince people to return their lives to normal if he tries to ease the lockdown soon.

The poll by Opinium, taken between Wednesday and Friday last week, found 17% of people think the conditions have been met to consider reopening schools, against 67% who say they have not been, and that they should stay closed.

Opposition to reopening restaurants and pubs – and allowing mass gatherings in sports and other stadiums to resume – is even higher. Just 11% of people think the time is right to consider reopening restaurants, while 78% are against. Only 9% believe it would be correct to consider reopening pubs, while 81% are against; 7% say it would be right to allow mass gatherings at sports events or concerts to resume, with 84% against.

Johnson, meanwhile, has given his first interview since he was released from hospital and disclosed that doctors had a plan to announce his death. He told Sun on Sunday that it was 50-50 that he would have to be put on a ventilator. “They gave me a face mask so I got litres and litres of oxygen and for a long time I had that and the little nose jobbie,” he said.

Once in intensive care he told how “the bloody indicators kept going in the wrong direction” and he realised there was no cure for Covid-19 and asked himself, “How am I going to get out of this?”

“But the bad moment came when it was 50-50 whether they were going to have to put a tube down my windpipe,” he said. He went on to praise the “wonderful nursing” that saved him and said: “They really did it and made a huge difference. I can’t explain how it happened. I don’t know . . . it was just wonderful to see them ...I get emotional about it . . . it was an extraordinary thing.”

On Saturday, the psychologist Prof Dame Til Wykes of King’s College London said the public’s reactions to easing the lockdown were likely to reveal high levels of anxiety. “It is likely that most people will feel anxious and risk averse.

“We have been given strict behavioural advice for more than five weeks, and when that is removed people will feel pressured, and individuals who had pre-existing anxiety, particularly about their health, will be worst hit. It will take quite a lot of psychological treatment to get over this.

“Different groups will be more affected than others, in particular the elderly and also parents, who will worry about their children bringing home the virus from schools.”

The poll figures, and warnings from experts, will fuel an increasingly tense debate inside Whitehall over how best to strike a balance between keeping the public safe and minimising damage to the economy in the next phase of the crisis.

Johnson said on Thursday that the UK had passed the peak of the virus but that people had to expect restrictions on their freedoms to remain in place for the foreseeable future. The prime minister will spell out his thinking later this week on how the lockdown could be eased when infection rates have come down.

The total number of deaths from Covid-19 in all settings rose on Saturday by 621 to 28,131. In total, 182,260 people had tested positive, an increase of 4,806 cases on the previous day.

At the Downing Street briefing, the communities secretary, Robert Jenrick, suggested that rules on what people could do outdoors would be relaxed earlier than those on behaviour inside, in places such as in pubs, clubs and restaurants. “The rate of transmission is significantly less outdoors than indoors, so when it is right to ease lockdown measures that will be a factor,” he said.

Dr Jenny Harries, the deputy chief medical officer, said that “generally, outdoor environments are safer” in terms of infection rates for Covid-19. But she said it depended how people travelled to an outdoor event and venue, and whom they went with.

Divisions within the cabinet and the Conservative party remain over how to proceed. The health secretary, Matt Hancock, is determined to take a tough line to protect the public, while the Treasury and many Tory MPs want to move to allow more people back to work to “fire up” the economy before many businesses go bankrupt.

The Opinium poll shows the government struggling to hold on to public support over its handling of the coronavirus crisis. The percentage of people who approve of its management of the crisis has fallen from 61% three weeks ago to 47% now, with the proportion of those who disapprove up from 22% to 34%. The net approval rate has fallen therefore from plus 39% to plus 13%. Given the fragile state of support, ministers will be determined not to misread the public mood over easing the lockdown.

Adam Drummond of Opinium said that views among the public over what to do about the lockdown seemed to differ from those at Westminster. “The public’s appetite for lifting the lockdown measures remains minuscule,” Drummond said. “Very few people believe that conditions have been met to allow for public spaces and venues to reopen on 8 May, and while some are treating the rules less strictly, few admit to breaching them.

“The clamour to ‘reopen the economy’ is largely taking place in Westminster and is not really reflective of wider public sentiment.”

The battle over Britain’s handling of the Covid-19 crisis comes as Ireland has decided to extend its lockdown for a further two weeks to 18 May, when it will begin a five-stage exit over three months, culminating in the phased reopening of schools and universities from 10 August.

In Spain, meanwhile, where adults were allowed out to exercise on Saturday for the first time since restrictions were put in place in mid-March, the prime minister, Pedro Sánchez, announced that anyone using public transport from Monday would have to wear a face mask. He also said that the government would seek MPs’ approval next week for another two-week extension of the lockdown, which is due to end on 10 May.

In Austria, people flocked to newly reopened hairdressers, beauticians and electronics shops, as they relished the loosening of a seven-week lockdown. France is proposing to impose a minimum 14-day quarantine on anyone arriving in the country from abroad after the end of lockdown on 11 May.

Jenrick announced a package of more than £76m in new funding to support the most vulnerable during the pandemic. It will go towards charities supporting vulnerable children and victims of domestic abuse and modern slavery.