Liverpool Street is to the east of London, by the City of London, a kind of eastern equivalent of Paddington.
If you are using Liverpool Street, you’re coming from East Anglia or Essex, so Norwich, Ipswich, Colchester (Britain’s oldest recorded city). However, as a traveller you have probably come from Stansted or Southend airports, or the towns of Harwich (Netherlands) or Felixstowe (though we think that’s not passengers), both busy ports, or even Tilbury.
It is the terminus of the Stansted Express, and you could also have come direct from Heathrow airport.