The ping limit for S1 is now 250 from 200 (raised) and S2's ping limit has been 250 for a while now.
Most east coast Americans with be fine while connecting to our servers, yet experience may vary for Americans that aren't on the east coast, sadly fiber can only transfer data at a certain speed around the world, which is limited by the speed of light (fiber optic) and any bad routers/cables between you and our servers (mainly rubbish last-mile connections - this is most likely your problem if you live in the UK and still get this issue). The latter you could potentially fix by calling your internet provider and complaining, yet if the limit is the speed of light, sadly it's slightly outside of our control...
The ping limit is enforced in order to ensure that the game experience doesn't feel too laggy - mainly people zipping around while in gunfights etc that could look like you were lagswitching, yet your ping is too high.
TLDR; If you get over 250 ping, and are far enough away to warrant that, then you may want to look elsewhere. If you are close to the UK and still get > 250 ping, it could be a problem that you could solve without breaking the laws of physics.... The ping limit is now 250 for both servers.