The government has been warned it faces "social unrest" and deaths if over-70s are told to remain under lockdown for longer than the young.
Doctors' leaders have piled pressure on Boris Johnson not to split people by age when he announces a "roadmap" out of lockdown this week.
The Prime Minister is expected to announce on Thursday that lockdown will continue for at least three more weeks.
However, he could announce some small changes. And he is then expected to set out a "roadmap" between now and next Sunday of how restrictions will evolve in future.
This has prompted fears that over-70s, who are more at risk from coronavirus than the population as a whole, could be asked to abide by stricter rules than others.
Scroll down for a full explanation of the current rules for over-70s - which don't ban you going outside.
This has not been confirmed or denied by government.
But the Sunday Times reports that ministers have discussed the idea of keeping older people under lockdown for months longer - even until a vaccine is found.
The possibility has also been discussed on the continent, including by European Commission President Ursula von der Leyen. She said last month: "I know that it is difficult and that isolation is a burden, but this is a question of life and death."
Former pensions minister Ros Altmann said separating people by age when lockdown is relaxed would suggest older people's lives "don't count in the same way"
The Tory peer told Sky News' Sophy Ridge on Sunday: "I think using an age-based criteria is fundamentally wrong and would potentially cost the lives of many people, and risk social unrest."
Baroness Altmann said many elderly people have only accepted lockdown conditions "because everyone else has got to do it".
She warned "lots of them" have said they would "risk going to prison" rather than continue isolating.
She added "nobody would dream" of applying restrictions on the basis of skin colour, despite a higher death rate among BAME people.
The British Medical Association (BMA) warned a “blanket ban” on healthy pensioners being allowed to return to normal life would be “discriminatory and unacceptable."
The doctors’ union added: “This needs to be based on individual risk that would apply at all ages rather than an arbitrary age of 60 or 70."
Martin Marshall, chairman of the Royal College of GPs, warned that prolonged lockdown would "impact" the "physical and mental health" of the over-70s.
He said age alone was not the best way to decide "who should self-isolate and to what extent during the next stage of lockdown".
Charity Director at Age UK Caroline Abrahams also spoke out against "blanket policies based on age".
And Comedian Sir Michael Palin, 76, told the BBC age restrictions would be "very difficult and very wrong and very unfair".
Contrary to reports in the Sunday Times today, the government has not told all over-70s to stay inside their homes for 12 weeks no matter what.
Instead, over-70s have mostly been told to be "particularly stringent" about lockdown rules because they are more vulnerable than other groups.
Health Secretary Matt Hancock today moved to clarify - saying "there is no 'blanket ban'" on over-70s going outside.
But he and other government officials have not ruled out the possibility of restrictions on over-70s in future.
What are the current rules for over-70s?
Over-70s are not currently banned from leaving their home for essential shopping or exercise - unless they’ve been individually told so by the NHS.
But campaigners fear that when lockdown is relaxed, older people might be kept under the rules for longer than younger people, for their own safety.
That proposal - which has been rumoured but is not in any way confirmed by government - has sparked a backlash among doctors' leaders and campaigners.
For now, the government has split people into three groups when deciding how strictly they must follow lockdown.
The strictest group, around 1.5million people with serious health conditions, have been told not to leave their homes at all for 12 weeks.
But this does not include all over-70s and indeed, includes many people who are under 70. Anyone in this group has been contacted directly.
The second-strictest group is all over-70s, pregnant women and those with a wider range of health conditions like asthma. They are not being told to stay indoors completely, but they are being warned to be “particularly stringent” in following lockdown rules.
Everyone else not in these two groups has to just follow the national lockdown in a standard way.
