Discount for cash

[craig1912]

Now retailers can’t charge a fee for credit/ debit cards- are they allowed to give a discount for cash payment, in effect charging you more for paying by card? My Indian Restaurant gives a 10% discount on take away but only if you pay cash.

[craig1912]

but is it illegal to give a discount for cash when it is clearly illegal to charge extra for a card transaction. Isn’t it one and the same thing?