Retailers and traders not allowed to charge you a surcharge for using your credit or debit card when making a purchase.
The rules apply to any UK company selling to UK consumers both in-store and online, and means customers using American Express, Paypal, Apple or Android Pay will also no longer face charges for using a different payment system.
The rules come from the EU Payment Services Directive, which replaced an old directive of the same name and as such is often referred to as PSD2.
This means the new rules were put into UK law - and so will continue to exist in the UK even after Brexit.
It is worth noting that the Regulations do not apply to public bodies carrying out public functions.
So, for example, payment surcharges levied by a local authority when providing a public function (such as renewing a driving licence) would not be subject to these rules.
We need your help to make sure companies do not abuse the rules.
If you spot any firm wrongly adding a surcharge for paying by card you can report it to Trading Standards.
Remember, you can shop around to avoid retailers that make additional service charges, and you can refuse to pay additional card surcharges.