Hounds from a Somerset hunt have been filmed apparently pursuing a fox, an animal welfare group has claimed.
The International Fund for Animal Welfare (IFAW) said the fox was shown running on a railway line at Clapton.
A few moments after the fox runs on the tracks hounds are then shown appearing but are called back by huntsmen.
A Countryside Alliance spokeswoman, speaking on behalf of the Seavington Hunt, said an investigation would take place into the incident.
Hunting foxes with dogs has been illegal since 2005 but they can chase a scent and flush out foxes who are then shot.
Avon and Somerset Police said its hunt liaison officer was investigating whether any illegal hunting had occurred while British Transport Police said no trespass offence had been committed as no people had gone on to the line.
The IFAW member who filmed the incident, who wished to remain anonymous, said it was “completely irresponsible”.
“I’ve seen a lot of things over the years I’ve been filming,” he said.
“This is a main line railway, I don’t know what would have happened if they’d have hit the hounds on that line.”
The hounds apparently pursued the fox on to a railway line
Alison Hawes, from the Countryside Alliance, which represents hunts, said an investigation would take place into how the hounds ended up on the track.
She said: “They were on there for less than two minutes and the hunt acted very professionally in calling them off the line as quickly as possible.”
Andrew Hudd, from the train drivers’ union Aslef, said footage of the incident was “shocking”.
“I estimate around a dozen [dogs were on the line] at one point which is a considerable threat to a train,” he said.
Network Rail has asked to see the footage.