The former prime minister said it was ‘not credible’ for the Government to repeat the sweeping draconian measures put in place back in March because of the economic damage another shut down would cause.
He said Britons must learn to ‘live with’ the deadly disease until there is a vaccine and that a mass testing programme is the only way to keep the country moving.
He took aim at the Government’s 14 day quarantine rules for people returning to the UK from countries where coronavirus is on the rise as he said the self-isolation period could be cut ‘substantially’.
He called for ministers to take a more ‘sensible’ approach to calculating risk amid rising speculation that Croatia and Greece could soon join Spain and France on the UK’s ‘red list’.
Meanwhile, Mr Blair also suggested ministers had been over reliant on officials during the crisis and that they needed to recognise ‘where the science ends and judgements begin’.
Boris Johnson has not ruled out imposing a second national lockdown should there be a major spike in coronavirus cases.
But Mr Blair told BBC Radio 4’s Today programme that another lockdown was ‘not possible’.
He said: ‘I just don’t think you are going to be able to do that and I think it was hard enough to do the first lockdown.
‘The economic consequences of that are obviously devastating but if you think about doing that in the winter months I just think it is not credible, it is not possible to do.
‘If you track what is happening around the world today I think countries are moving in the direction of this mass testing.’
Mr Blair has long advocated the introduction of a mass routine testing programme in order to stop the spread of coronavirus in the community.
He said that such a programme is necessary because as many as 70 per cent of cases are asymptomatic.
He said the Government ‘has got to change the way it calculates risk’ as he called for quarantine rules to be relaxed.
Ministers announced last week that travellers returning from France must now self-isolate for two weeks.
The Government has faced sustained pressure from the travel sector and Tory MPs to ease the rules.
Mr Blair said: ‘In every single aspect of this, once you realise you are not going to eradicate the disease, you are going to have to contain it and live with it at least until a vaccine comes, then you have just got to have a sensible risk calculus in every area.
‘So for example now we are telling people to go back into pubs, we are incentivising them, quite rightly for the purposes of getting the economy moving, to go and eat out.
‘All of those things are risk. I think the way we are doing the quarantine rules is wrong actually, I think you could cut that 14 day quarantine substantially.
‘If you recognise that whatever you do there is going to be a risk, you just have to minimise it.’
Mr Blair also called for more political leadership during the crisis as he suggested ministers had tried to shift responsibility for key decisions to the Government’s science and health experts.
Ministers have said throughout the pandemic that all of their decisions have been based on the latest official advice.
Mr Blair said: ‘In the end the important thing when you are in government and officials are giving you advice, is the hard thing is sometimes not finding the answers but finding the right questions.
‘You have just got to interrogate the officials properly and I think what has happened is that too much of this has just been, as it were, accepted without really trying to get underneath and into the detail of what people are suggesting so you understand where the science ends and judgements begin.’