Literally right next to St Pancras. There’s an historic old bit and a nice modern bit. And it’s always busy.
If you are arriving here, you have probably come down the east coast, from Edinburgh, Newcastle, York (a big tourist city), Peterborough, Hull, Lincoln, Leeds… it’s a long list.
Underground
It’s exactly the same as St Pancras, with different entrances. There’s an entry just off the left of this picture above between the two mainline stations and going down some steps, and the new section takes you down using more escalators, right at the back on the left (below where the picture was taken). There are also some lengthy passage ways to trek.
(The worst thing about this part of the station is the mob of Harry Potter fans queuing up to stand by a wall).
Taxi
Same as St Pancras. The taxi rank is at the west side of the station.
Bus travel
The same principle as St Pancras.
Buses stop in front of the mainline station, heading east towards Islington, Stoke Newington, and at the east (right) side of the station (heading north). Many buses terminate here.
To head towards central London, you will need to cross the main road and it is tricky.
And the one way system is beyond confusing.