An investigation was underway after 500 guests were evacuated and 14 people were injured in an explosion at a top central London hotel, London Evening Standard reported on Saturday.
The gas explosion at the five star Churchill Hyatt Regency Hotel in Portman Square left five people needing hospital treatment.
Around 80 firefighters attended after emergency services were called to the scene in Marylebone at around 11.40 on Friday night.
Police said all of the guests are now accounted for.
Firefighters used specialist equipment to tackle the collapsed buildings, the London Fire Brigade said.
Five people needed hospital treatment and nine others were checked over at the scene and given the all-clear.
One guest described the scene outside the hotel as "chaos" after the explosion.