Public Health England's head of immunisation Mary Ramsay today suggested safety measures could be in place until other countries had successfully rolled out vaccine schemes.
Ms Ramsay also indicated big spectator events would not simply go back to normal and would require monitoring and new safety instructions.
She said: “People have got used to those lower level restrictions now, and people can live with them, and the economy can still go on with those less severe restrictions in place.
"So I think certainly for a few years, at least until other parts of the world are as well vaccinated as we are, and the numbers have come down everywhere, that is when we may be able to go very gradually back to a more normal situation.
"We have to look very carefully before any of these restrictions are lifted.”
The stark warning came on a morning a member of the Joint Committee on Vaccination and Immunisation claimed a “very large number” of at-risk people could develop a “serious” Covid-19 infection if restrictions are lifted now.
Professor Jeremy Brown said between 90 per cent and 95 per cent of people who are at risk have been vaccinated, but that one dose does not provide full protection.
He told Sky News’ Sophy Ridge on Sunday: “Until we have done the second dose and everyone has been vaccinated, there is a little degree of infection that still occurs.
“If you completely lift all restrictions there will be a wave of infections across the country and those who are not protected, either because the first vaccine hasn’t worked very well in them and they need their second dose, or because they have not had a vaccine at this point in time but are still vulnerable, they will get infections and they will end up in hospital and die.
“So, if you lift restrictions, even though most people who are at risk have been vaccinated, the proportion who have not still represent a very large number of people who could end up with serious infection.”
The UK government's chief medical adviser Chris Whitty earlier this month suggested "simple interventions like washing hands, face masks where appropriate, test-and-trace, and above all vaccines" would keep the virus controlled beyond Summer.