Flames reported at the top of Blackpool Tower were actually “orange netting”, police have said, after firefighters rushed to the scene.
Lancashire Constabulary flew a helicopter over the tower and confirmed there was no blaze.
The 158-metre structure is currently closed for renovation.
The fire service was called to the scene by “concerned members of the public”.
A man has been arrested on suspicion of breach of the peace, police said.
A police statement said: “We know there are reports of a fire at Blackpool Tower and we just wanted to give you an update from our divisional commander, Chief Superintendent Karen Edwards.
“We are at the scene in support of Lancashire Fire and Rescue Service, Blackpool Council and Merlin Entertainment.
“The top of the tower is currently closed for renovation and difficult to access. Our helicopter has flown over the tower and there is no fire.
“We can confirm what can be seen is orange netting.
“One man has been arrested on suspicion of breach of the peace and is being transported to custody.”
Lancashire Fire and Rescue Service had six fire engines in attendance on the promenade and the tower was evacuated as a precaution.
The fire service said in a statement: “Lancashire Fire and Rescue Service were called to Promenade, Blackpool today by concerned members of the public, due to a combination of factors that led them to believe it was a fire.
“The area where the fire was suspected is generally inaccessible, therefore access to this area is difficult. A specialist team from Lancashire Fire and Rescue Service gained access and confirmed that there was no fire.
“This incident was supported by the National Police Air Service, who used thermal imaging which provided further assurance.”
A spokesperson for Merlin Entertainments, which runs the tower, said: “We can confirm that the fire brigade are on site at the Blackpool Tower and have established that there is no fire.
“Our well-rehearsed emergency procedures were implemented, and we can confirm that what looked like a fire from a distance was in fact lights on a reflective netting surface at the top of the tower.”
No smoke was reported but an investigation was carried out as a standard procedure, the company said.
The surrounding area was evacuated as a precaution.