Lol!Text taken from the citizens advice website UK ...
If something is advertised at the wrong price
This advice applies to England Print
If something you want to buy is advertised at the wrong price, you may be able to buy it at the lower price.
Buying in a shop
Your legal rights in a shop will depend on whether you’ve paid for the item yet or not.
If you haven’t bought it yet
If you take an item to the till and are told the price on the tag or label is a mistake, you don’t have a right to buy the item at the lower price. You could still try asking the seller to honour the price.
It’s the same if you see an item advertised anywhere for a lower price than the one on the price tag.
Of course!
Read what it says! You pay for the price advertised. Of course if you payed higher you can't go back and claim the new price is lower!
Begorrah!
That saying about the Irish is true.
Point is. In the UK it is honoured. A gentleman's agreement as it were.