MVNO stands for Mobile Virtual Network Operator.
An MVNO is a mobile provider that doesn't own its own mobile network. Instead, it buys access to one of the major networks and sells mobile services under its own brand.
Provider Type Underlying network
EE Main network EE
O2 Main network O2
Vodafone Main network Vodafone
Three Main network Three
Lebara MVNO Vodafone
giffgaff MVNO O2
iD Mobile MVNO Three
MVNOs usually provide cheaper packages than main network operators.