A fire that destroyed a historic hotel is believed to have started by a “carelessly” discarded cigarette that was blown against the building by strong winds and set an old window frame alight.

Crews from as far as London descended on The Royal Albion Hotel in Brighton as it went up in flames during the major incident on July 15 last year.

A large area of the city was covered in thick smoke and police closed off the Old Steine and part of the A259 King’s Road to traffic due to health and safety concerns, with fears that the building could collapse.

It was around 5pm when flames burst through the windows on the west side of the 200-year-old building.

Strong winds from the shore fanned the fire and it was not long before it spread across several floors and up into the roof of the Grade II listed building.

The burnt out hotelThe burnt out hotel (Image: Supplied)

It took days for the flames to be extinguished with smaller fires erupting at times.

The Fire Brigades Union claimed firefighters worked 13-hour shifts and were forced to urinate in buckets as they fought to extinguish the blaze.

Residents in nearby flats were forced to leave their homes due to the fire, with some still not able to return several months on from the blaze.

Demolition work began five days after the fire.

An investigation report from East Sussex Fire and Rescue Service has now revealed further details on what happened that fateful day.

Investigators were satisfied the fire was not deliberate and that it started on the external wooden windowsill and frame of room 330 at 5.05pm.

They said this was likely caused by a “carelessly” discarded cigarette that was blown back against the window by strong winds.

They said the fire spread quickly through “hidden voids” in the hotel.

Read more: The fall of Brighton's Royal Albion hotel

A man and woman from Hong Kong, who were staying in the room, had returned home before the fire service could speak to them.

Once contacted they denied smoking in the room.

“The man and woman from Hong Kong arrived at the hotel at 15.56 hrs,” the report said.

“They spent some time in the room before heading out to do sightseeing. It cannot be proven that anyone smoked within room 330 but the most probable cause of this fire is a carelessly discarded cigarette, either by one of the occupants of room 330, or by an occupant of a different room who had discarded a lit cigarette out of their window, which had then blown back against the building and nestled within a crack within the dry timber window frame for room 330.

“The exceptionally strong wind speed blowing directly against the window frame then created perfect conditions for fire development and spread. It soon engulfed room 330 and beyond due to the readily combustible materials within the walls and ceilings and multiple hidden voids throughout the building, which enabled fast-paced smoke travel, highlighted by the fire alarm system report, which reported smoke detection on the 1st floor of the hotel, even before the arrival of the fire service.”

The assistant maintenance manager and maintenance assistant took this picture of the fireThe assistant maintenance manager and maintenance assistant took this picture of the fire (Image: East Sussex Fire and Rescue Service)

Investigators praised the quick evacuation of hotel guests by “competent and well-trained” staff who started the procedure as soon as they discovered the fire.

There were no casualties due to the rapid evacuation and only one record of an injury which was someone getting smoke in their eyes.

“Had this incident occurred during nighttime hours, where fewer staff were available, then this incident could have had far worse consequences,” the report said.

The report detailed how staff were alerted when the fire alarm sounded at 5.20pm and went to investigate the room.

It said the fire alarm system was reset by hotel staff at 5.05pm and 5.06pm.

A manual call point was activated at 5.18pm.

“They could both smell smoke within the corridor leading up to the room,” the report said.

“They entered the room together, there was no one within the room and there was no fire, and nothing unusual, but they could smell smoke.

“There were no reflective objects in or around the window. When they looked out of the window, they could see a lot of smoke but no flames coming from the window frame. They decided to move to a different position to get a better look, so they moved into a room the next floor up. As they looked out of the window from the room, the smouldering fire suddenly became a flaming fire.”

Firefighters battled to extinguish the blazeFirefighters battled to extinguish the blaze (Image: The Argus/Andrew Gardner)

999 was called and the evacuation began.

The investigator was told that people were known to smoke on the window ledges in the hotel and that often discarded cigarettes found at the base of the hotel would have to be cleared away but that no cigarette butts were seen within cracks in window frames.

The hotel manager said they had a zero-tolerance policy towards smoking in rooms.

The investigator said another fire occurred at the Harbour Hotel, which is 500 metres along the seafront from the Royal Albion, a week later in "very similar circumstances".

A  wooden windowsill had completely burnt away with no obvious ignition sources.