A fire has broken out at Harrow's Northwick Park Hospital, forcing the evacuation of 200 patients and staff.
Fifty firefighters in eight engines - largely a precautionary measure - are helping to tackle the small blaze in the main block of the hospital in Watford Road, Harrow, that started at around 3.15pm.
Michelle Witton, 41, from Willesden, was evacuated from level seven.
She said: "I've been in hospital for five days. We were told there was a fire and we needed to evacuate. I smelt smoke in the stairwell and the fire stairs looked like they had not been cleaned for years.
"There were bags of rubbish and furniture. That was the only way patients could get out and I am going to take it up with the hospital."
Carol Hallal from north Wembley, who had an operation on her spine last Friday, was helped down the stairs by two physiotherapists.
She said: "I was evacuated from level 10. I was really scared. I didn't know what was going on. They just said there was a fire and we needed to get out."
A spokeswoman from the hospital denied any exit routes were obstructed with rubbish or furniture and said "all the walk ways were clear".
Harrow fire station manager John Doherty told the Observer: "We have got a fire in an electrical intake room in the basement area and because of the spread of smoke, we're in the process of evacuating a major part of the hospital. That's about 200 people."
Mr Doherty said he had colleagues in breathing apparatus putting out the fire, and so far there were no casualties or injured and no permanent building damage.