What Pilot License is required for a Twin Engine aircraft?

I know that a Private Pilot License is required for a single engine aircraft. But what License in required for a twin engine?

Also, any websites that will help me out with what the budget of it is. As I’m from the UK, only UK Sites please if it has prices.

Any site please if it has a lot of information about it all.
I fly in the UK because I’m FROM the UK and thats where I live. I’m not going to U.S to fly a plane.