Over the weekend, I noticed that Sainsbury’s (and, I assume, the other supermarkets) are now operating a “Think 25″ policy, where if you’re buying items that are prohibited under a certain age, you’ll get asked for ID first.

What items are we talking about? Well, to my knowledge – and this isn’t a comprehensive list, although I could probably find one if I tried – it consists of :

• Cigarettes  (18 or over – it used to be 16, but changed in October 2007)
• Alcohol (18 or over)
• Blades – knives, razor-blades etc. (18 or over)

It used to be that if you looked under eighteen, you’d be asked for ID. Fair enough – 18 was the limit for most of the age-limited items.

Then the stores started getting paranoid about customers who just “looked” 18 getting through the system, so they invoked the “Check 21″ policy, where even though you were legally allowed to buy said products, if you looked up to three years older than that, you would still get asked for ID – and not allowed to purchase the products if you didn’t have ID.

Now they appear to be even twitchier about it, and the “ask for ID” limit is 25 – and that’s if you look 25, not whether you are or not. So a whole seven years more of being asked for ID.

And the really stupid bit? The entire thing is voluntary – which means it’s perfectly legal for the only-just 18 till-person to sell the (for example) beer, but ask ID of someone who looks up to seven years older before they can sell it.

Totally barmy.