In the United Kingdom, it is not considered rude to pump your own gas (known as petrol in the UK) at self-service stations. In fact, self-service petrol stations are common throughout the country, and many people prefer to pump their own fuel for convenience and speed.
Unlike some other countries where full-service stations are more prevalent, the majority of petrol stations in the UK operate on a self-service basis. Customers are expected to fill up their own vehicles and then proceed to the payment kiosk to pay for the fuel.
While it is entirely acceptable and commonplace to pump your own gas in the UK, you should always follow the rules and guidelines at the petrol station, including any safety instructions and payment procedures. Also, keep in mind that in some rural or remote areas, you might come across a few full-service stations where an attendant will assist you with pumping the fuel if self-service options are not available.