The signs aren't always very clear. King's Cross being the worst culprit. Arriving on the Northern Line then changing to the Circle line, will take a few minute

The signs aren't always very clear. King's Cross being the worst culprit. Arriving on the Northern Line then changing to the Circle line, will take a few minutes or almost 10 depending on which end of the train you get off. This happened to me a few weeks ago when I blindly followed the signs right in front of me. The directions are different depending on which end of the train you get off.