Boris Johnson said easing England’s lockdown will be based on a “cautious and prudent approach”, as he was urged to focus on data rather than dates when lifting restrictions.The Prime Minister stressed that any easing of restrictions needs to be done in stages and said his road map out of lockdown on Monday will be done in a way that ensures it is “irreversible”.Mr Johnson was asked, during a visit to a vaccination centre in South Wales, whether he agrees with Professor Dame Angela McLean’s comments to the Commons Science and Technology Committee that any unlocking should be based on “data, not dates”.