Leeds
Liverpool and Manchester.
In the 21st Century every city in Great Britain has roads
Departure point: Kansas City, Kansas/MissouriDestination point: Denver, ColoradoEstimated flight duration: 2 hours, 29 minutes
London is the capital of England and of the United Kingdom of Great Britain and Northern Ireland. Great Britain consists of England, Scotland and Wales. The UK consists of Great Britain and Northern Ireland.
Great Britain is neither a city nor a state; it is an European country, otherwise known as the United Kingdom.
Departure point: Kansas City, MissouriDestination point: Palmero, ItalyEstimated flight duration: 10 hours, 24 minutes
New York
Departure point: Salt Lake City, UtahDestination point: Denver, ColoradoEstimated flight duration: 1 hour, 16 minutes
Great Britain is formed from England, Scotland and Wales. The United Kingdom is Great Britain and Northern Ireland. So the answer is YES, Great Britain is part of the UK.
Between 20.5 and 23 hours depending on the destination city and point of departure.
We wouldn't be able to speculate without knowing the point of departure.
It was not in Rome, which was a city. Brindisium was a port in eastern peninsular Italy which was a departure point for the east.