Police said they have not established a motive for the attack on the horses. Reuters

The tails and manes of fifteen horses were hacked off by intruders at a Scottish farm.

Thieves broke into a field near Waterhead Farm, in Cumbernauld near Palacerigg Country Park, on 7 November, when they carried out the bizarre attack.

Police were called after the horrified owners discovered the horses had been mutilated overnight.

A spokesperson for Police Scotland said: "We received a report of 15 horses having parts of their tails and manes cut off. It is believed to have taken place overnight when the horses were out in the field, near Waterhead Farm in Cumbernauld. Inquiries are continuing."

Officers stressed that the animals were not injured during the "mane hacking" incident, since their tails were cut off below the bone, however they may have been left distressed by the ordeal. It will take a decade for the tail to grow back.

Police have not been able to establish a motive for the crime and have not said whether it was theft or an act of mindless vandalism.

Horsehair is widely used in upholstery, fishing lines, violin bows, belts and brushes and is mostly imported after docking was banned in the UK in 1949.

The attack earlier this month was not the first on horses in Scotland. Two horses had their forelock and manes hacked off in the space of a week in the Lothians and in 2012, one animal was targeted in the Bonally area of Edinburgh, and another in West Lothian

Police are warning horse and pony owners are to be vigilant after the incident.

Anyone with information is asked to contact Police Scotland on 101.