Small, no lock, but the host lives in the same apartment, which we didn't realize he also lived there full time. Once we cleared up the situation the next day, he was very helpful and hospitable. The location was great, just steps away from the Piccadilly line underground. The area was a little shoddy but we had no problems and found everything we needed. We took his advice reference purchasing an "Oyster Card " for the underground and it saved us a bunch of cash and problems. Overall, we had a good experience if you accept the fact that you're in London and not in the US.