Plugs in the United Kingdom are a bit different from what we are used to, so we will tell you below which plug you will find in your hotel room if you are going to visit London or any other city in England:

This is the wall socket you will find when you come to England, a three pin socket. And you will see that next to the plug there is a switch to turn the plug on or off.
This is the UK 3 pin plug.
And this is the adapter that you can get to be able to plug your two-pin plugs into the three-pin plug here. You can buy this adapter in Spain, in the English Court they usually have, at the airport in Spain and in England on arrival as well. Yes, it is true that they will be more expensive at the airport, since they can be found quite cheaply in London markets and in many souvenir shops in the city centre.