Take a look at the presidential proclamation. If you’re not a US citizen or resident (or their family), or on certain visa types, you won’t be allowed in if you’re coming from the U.K. It’s possible to go to a third country for 14 days before entering the US (lots of discussion here about people who absolutely need to enter the US doing a 2 week trip to Mexico first). Otherwise there is a process to get a waiver from the US government but they are pretty tough to get.