A train was almost derailed when a gas canister was thrown on the tracks near Swanley station.

Police say it was just "sheer luck" the Gillingham to London Victoria service did not come off the tracks when it hit the container.

Detectives are appealing for witnesses to the incident, which caused delays across the area on Saturday morning.

DS Tony Samiotis, from British Transport Police, said: "The 10.21am Gillingham to London Victoria service hit the canister between 10.45am and 11.05am, as it was travelling roughly half a mile south of Swanley station.

"We believe the gas canister was thrown onto the tracks and we are appealing for anyone with information to come forward."

"Trains travel at high speeds and there is a very real risk when they strike objects on the track that they could be derailed..." - DS Tony Samiotis

Officers are making local inquiries, including identifying forensics, speaking to witnesses and looking at CCTV.

Mr Samiotis added: "Fortunately, no one was hurt during the incident, and the train remained upright on the tracks. However, this was just by sheer luck and the consequences could have been far worse.

"I cannot over-emphasise enough the dangers associated with this type of crime, it is vital that we find those responsible. Trains travel at high speeds and there is a very real risk when they strike objects on the track that they could be derailed.

"We are urging anyone who was in or around that area to contact us if they saw anything suspicious or have any information that may help us with our enquiries."

The incident, which caused damage to the train and tracks, also caused delays of more than 100 minutes to trains.

Anyone with information is asked to phone police on 0800 405040, quoting reference B11 of 24/06/13, or Crimestoppers, anonymously, on 0800 555 111.