Up to 70 firefighters have spent the night tackling a huge fire at a derelict seafront hotel.
Two people have been arrested after the Palm Beach Hotel went up in flames at around 1.30am on Thursday.
Fire crews remain at the scene, where it was still unclear as to whether anyone was inside this morning.
Tom Goodwin, 27, of the nearby Waldorf Hotel called police in the early hours to report a man acting suspiciously at the front of the hotel on New South Promenade, South Shore.
When police arrived they noticed a light on in a second-floor bedroom of the hotel, which has been empty for a number of years.
A spokesman for Lancahsire Fire and Rescue said as the light grew more intense, the officers realised the hotel was ablaze.
She said: “The fire began on the left hand side of the hotel, as you look at it from the promenade.
“It spread and developed quickly. On top of that we had the wind coming in from the sea.”
At its height, there were 12 fire engines at the scene and 70 firefighters.
The spokesman said the flames were finally out by around 5am, after part of the hotel’s roof collapsed.
Up to 30 people from Clifton Drive, which runs behind the hotel, were believed to have been taken to South Shore Academy, on St Annes Road, after their homes were evacuated for safety.
Rossalyn Tindall, of Clifton Drive, was told to leave her home at 1.45am as firefighters battled to get the blaze under control.
She went to the nearby Solaris Centre, where she works, and said she spent the morning waiting for the phone call to say it was safe to go home.
She said: “I think we are all very lucky the fire crew and police were on the scene so quickly.
“Hopefully nobody was hurt but we all felt there might have been somebody inside.
“To be honest, it’s something we were expecting to happen sooner or later.
“Most of the residents have complained about the state of the hotel. There’s been fly-tipping and people breaking in and living there.”
“The Number One South Beach Hotel had no electricity so I’m assuming they had to switch it off.”
Two men, aged 38 and 39, from Blackpool have been arrested on suspicion of arson and are in police custody.
Arvind and Monique Patel secured planning permission in 2009 for a £14m redevelopment of the Palm Beach Hotel which they owned.
But the scheme - to replace the existing building with a 120-bedroom new hotel rising to 11 storeys - has never gone ahead.
It was designed by architect Ian Simpson who designed the 50-storey Hilton Hotel in Manchester, and backed by Peter Moore, a former consultant on the Blackpool Masterplan.
In the same year, outline planning permission was granted for a mixture of residential development at each end of Bourne Crescent, with two separate projects approved for the redevelopment of hotels including The Colwyn, The Skye, The Trafford, The Sandpiper and The Headlands.
A third scheme for 11 storey high residential development of the remainder of Bourne Crescent comprising the Kimberley, Waldorf and Henderson hotels failed to secure planning permission from the council.
It proposed a £40m investment in an 11 storey apartment block of 166 apartments.
But planners threw out the scheme saying it failed “to make any significant provision for holiday accommodation” which it was feared could set an “adverse precedent” on the Promenade.