Our company, Folklore Productions, represents many UK-and-elsewhere in the world-based artists, and I am the person who files the visa applications that gets them into the U.S. for their tours.

Thers are so many variables that I can't even begin to list them, but the main thing to remember is that the artist's US-based booking agent (or whoever is the petitioner for their visa) MUST allow enough TIME. There are a lot of steps to go through, and each step takes time. Most of the cases that I have heard of that resulted in an artist being denied a visa were because the application process was not started soon enough. Also, each step is closely checked for accuracy, and one little mistake sends the whole thing back to square one for redoing.

I am not by any means happy about the system as it stands, but my (15 years of) experience has been that if a visa is properly applied for in good time, all backup documentation is provided, and every i is dotted and t is crossed, the visas do get granted. Still, you never know what will set off an alarm; one artist we used to represent had a teenage minor delinquency on his record; thirty years later, and after many successful US tours, that long-ago charge was still slowing down his acceptance, every single time. Go figure.