A call was placed to police at around 3.30pm by a woman who claimed that she had seen the animal near the railway line at Shepley, a small village near Huddersfield.
A police helicopter and around 12 officers were dispatched to look for the lion. Passengers were also held on trains at Shepley station, according to National Rail Enquiries' official Twitter account.
Inspector Carlton Young of West Yorkshire Police told PA on Sunday evening: "We've had unconfirmed reports of a lion or a lion cub in the area. We've had officers looking around.
"At the moment we've had nothing confirmed and we've not located anyone who is claiming to have lost an animal."
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The team behind the National Rail Enquiries Twitter feed - which usually only broadcasts short status updates and responses to customer queries - spent most of the evening interacting with users, including a joke account set up in the name of "Shepley Lion".
They quipped that the lion "does work hard to ensure there's no fare dodging", and linked to a user's photograph of a person in a lion suit sitting on a train platform, joking: "Someone has just sent me a photo of it for proof."
The search was called off at 5.15pm and no lion was discovered, although police did say that the operation would resume if there were any additional sightings of the creature.
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