The virus has not gone away, the lockdown was to protect less than 10% of the population who are vulnerable or elderly and to protect the NHS. If people go shopping, so what. Just don’t go to see your elderly relatives. I wouldn’t be surprised if the govt extended the lockdown for shielded and vulnerable including elderly but let the rest of us out.
I know that seems like a simple and logical solution, but it's not "job done, we've protected the nhs, now we don't have to any more". The nhs will only stay protected so long as the amount of virus circulating is as low or lower than after lockdown.
It's also not just about protecting the vulnerable. High levels of virus spreading through the community, even just amongst younger or otherwise less vulnerable people, will not be ok for anyone. As well as health services being overwhelmed again, people won't spend money or go to shops or get their children educated if levels of illness go up to high levels again. The tourism and hospitality industries will stay crippled. Vital services like dentistry will stay limited.
No matter how we do it, we all have to keep levels of virus in the community at a very low level that can be kept track of by testing.
That's without even taking into account the fact that the most vulnerable people don't all fit neatly into a box that can stay at home easily. I don't want my local hospital's top paediatric consultant, who might be a BAME man or someone with diabetes, to have to stay at home for months or years. What about a child's best friend, or the local dentist? It's not all conveniently old and frail people.
The only way we can have a semblance of normality is if we have extremely low levels of virus circulating. We don't want lockdown to be the way we do this anymore - we can't afford for lockdown to be the way we do this any more! But we still have to have it as the goal, even while we're opening things up again and gradually seeing more people. We can achieve it too if we have good tracking and tracing and if we do things in safe ways.
A lot of this is up to us.