I recently stayed at the Carlton when business took me to London during Wimbledon and all the standard business hotels were either full or ridiculously expensive. After reading all the terrible reviews I was fearing the worst, but it turned out fine and wanted to contribute a fair review.

Sure the location isn't fancy, but it's right across from King's Cross/St. Pancras for easy access to tube and rail (a very short tube ride to Soho, Covent Garden etc.) and I found a number of nice pubs a short walk past the station down Euston Rd.

My room (#8) was a few doors down from the main office on the ground floor. It was quite small and basic, but was also perfectly clean and covered all the basics - twin bed, desk/chair, TV, ceiling fan with light, reading light, bathroom with stand-up shower. Other than a very slight noise from nearby plumbing - less intrusive than noise I've had at much more expensive hotels - the room was quiet and I had no trouble sleeping.

The hotel staff were very friendly and helpful, free wireless internet is available in the main lounge and the included breakfast (eggs, toast, sausage, ham, beans, juice) was great. In fact, I had to leave a bit early to catch my flight and she brought out a breakfast for me 20 minutes early. I couldn't expect much more for the price in London.

The area around King's Cross and the new St. Pancras International Rail Terminal has never been one of London's more desirable locations. But if you are exhausted coming off a long train ride or need to leave on an early train, this place is safe, clean, and comfortable. If you are carrying heavy suitcases, this is one of the few inexpensive hotels near the station with a lift (elevator). The rooms are plain and some have quirky shapes. But the beds are clean and comfortable, the front desk staff marvelous.
Early in the evening, the police and ambulance drivers seem to favor nearby Euston Street, but seem to take other routes at other times of the day. So there will be some street noise, but it should disappear by bedtime.

I did not even stay at this hotel and I was charged for it. The website makes the place look very nice, I booked then read the reviews on trip advisor and cancelled as they were so bad. I received an email to say it had been cancelled. When my credit card bill arrived they had charged me. I phoned every day for a week and every time there was an excuse about the manager not being in or busy. The man on the phone was very rude.

It's very convenient. It's not luxury but has all necessary amenities and clean. I will use it again.