But can anyone cite any actual law a checkout worker would break if the worker asks for ID for an age-restricted product, the customer does not provide ID, the checkout worker sells the product anyway, and the customer is in fact old enough.
Under the Licensing Act 2003, it is mandatory for all licensed premises in England and Wales to adopt an age verification policy in relation to the sale or supply of alcohol.
So for shops, it is a condition of their licence that they apply an age verification, and for most it is Challenge 25. The minute a worker asks for ID and then sells the item - regardless of the purchasers age - without having seen the ID requested they are breaking a condition of the licence which then has them in breach of the Licensing Act 2003. The penalties are personal fines for the person who sold it as well as fines for the store and potential loss of their licence, so even if the store manager vouches for a customer, I will not process a transaction where I have asked the person for ID until I personally see it. If the manager wants to process the transaction then they're welcome to but I won't and most good managers would never put their staff in that position as it is an abuse of their position and could result in them being disciplined if the staff member raises a grievance (especially in large supermarket chains like mine)
Also some companies (mine included) hire test purchasers who are all over 18 to try and buy age restricted items to ensure staff are applying the policy correctly. The company my store uses gives the purchaser a scenario which may include them trying to persuade the cashier with various excuses to change their mind to see if they stick to the "No ID. No Sale. No Exceptions" eg "My friend X works here, can you get them to come and verify I'm old enough?" or "I dont have my ID but I have a picture on my phone, is that OK?" or "I'm over 18, look I have tattoos/car keys/kids" etc etc.
At the moment it is also difficult as everyone is wearing masks so it is easy to not recognise someone and have asked for their ID before you realise that they are actually 25+ (my Aunt came up to the customer service desk where I work yesterday and I didnt even recognise her until she spoke to me because I have never seen her wearing a mask) and you have to gauge "Are they 25+?" from the eyes up as we are not allowed to ask people to remove their mask before we challenge them, so many people are being overly cautious. If we ask for their ID and cannot be sure it is the person we can request they remove their mask, but they have the right to refuse and if they do so then we are not allowed to complete the sale.