British people are the native peoples of the British Isles and United Kingdom. Revelation TV is a British company, and Gapehorner is British. The original caller to Duncan was w3baholic, a British prank caller.
The most famous British prank call victim is The Respected Gentleman, possibly the most famous soundboard victim after Duncan and Tom the Roofer. Another British victim, discovered by Gapehorner is the Ignorant Lady, who lives a few meters away from the Brendan Chase. During voice calls, Americans will often comment on the caller's accent if they are British. British victims can either be calm but rude or hugely angry. There doesn't seem to be an in-between.