Police are investigating after footage surfaced of a couple appearing to have sex on a ScotRail train.

More than 500,000 people have viewed the clip on social media - which appears to show a man and woman engaging in lewd acts on an empty carriage.

The two minute long clip of the train's CCTV is thought to have taken place on a journey between Glasgow and Edinburgh.

It was posted on Twitter on Saturday evening.

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British Transport Police are appealing anyone with information to come forward.

A spokesperson for ScotRail said: "Anti-social behaviour has no place on Scotland’s Railway, and we will continue to work with the British Transport Police to clamp down on unacceptable conduct."

And a British Transport Police spokesperson confirmed to the Evening Times: "We are aware of this footage and are making enquiries.

"Anyone with information is asked to contact British Transport Police by sending a text to 61016 or by calling 0800 40 50 40."