Owners of the Richmond Harbour Hotel Spa said maintenance work was being carried out on the roof when the blaze broke out on Tuesday night.

Fifteen fire engines and around 100 firefighters spent all night battling the blaze and were at the scene all day Wednesday.

London Fire Brigade said the leisure complex and pool building was destroyed by fire and part of the third floor and roof of the adjoining hotel annexe was also damaged.

A statement from the hotel owners said: “It is with regret that a fire at the Richmond Harbour Hottel Spa has caused extensive roof damage.

“The cause is as yet unknown but maintenance was being carried out on the roof by external contractors.

“Fortunately due to the efforts of the emergency services, the damage was largely contained to the spa and we are extremely grateful.

“Harbour has created a world class Spa in Richmond and work will commence imminently to restore it.”