Dialing from Toronto to London
011 44 20 X
Number 011 is the international prefix used to dial somewhere outside of Canada.
44 is the international code used to dial to U.K..
20 is the local area or city code used to dial to London.
X is the local number you are calling.
011 44 131 X
To call Canada from the UK
Area code (416 or 905) and the phone number.