on 21-09-2015 19:30
Actually, @MI5, you can use 01144 to call the UK from the US. It's the alternative to +44 if you're calling from a land line and don't have the + feature on your phone. After you use either code you leave off the first zero of the UK number.
Found this handy calc online too
OnePlus 6 (O2 & Sfr), Z3 Tablet (Three UK), iPhone 8+ (EE)