Do not use the NCP carpark in London, Royal Garden Hotel! We prebooked and paid for all day, arrived on time however the barrier wouldn't go up. Tried the call button on the machine, not in service, tried to phone on my mobile no signal as we're now 2 floors down under ground. Had no choice but to ask machine for a ticket to open the barrier. As we drove through it was dark and dingy, some lights didn't work and there was noone about(advertised it said manned car park with security). There was a smell as we drove around, then we saw sewage all over the floor, what I presume was from the hotel above, we've never smelt anything like it, it was disgusting! We had an appointment so had to leave the car and go, but I tried to phone numerous times concerned about the fact I got a ticket even though I'd prebooked. The online chat doesn't work. It ruined the day, and stressed me out trying to contact them and worrying about paying twice. Once we were ready to leave the barrier again wouldn't open, the call button on this machine however did work but it took 10 mins just to leave once we got through to someone. Will never use again, avoid avoid all costs!