Police are facing fury after officers rammed a terrified cow with their squad car, as their force referred itself to a watchdog following demands for an explanation.

Home Secretary James Cleverly has been among the critics over the 'heavy-handed' approach taken by Surrey Police against a frightened calf in the middle of the road in Staines-upon-Thames.

Eyewitness Kai Bennetts, 22, told of being 'disgusted' at seeing the police ram the animal - saying how it was left with an 'open gash' and 'loads of grazes where the skin had come off' on being hurled several metres down the street.

Reports suggested the animal was knocked over near Bedfonts Lake Country Park in Hounslow, west London, while there has previously been a herd of cattle about three miles away at Saint Dunstan's Meadow in Feltham.

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Surrey Police has now announced that its Professional Standards Department has been informed and it will voluntarily refer to the Independent Office for Police Conduct for a further investigation.

Calls have been made for the 'monsters' who rammed the calf to be sacked after a new video showed the bovine calmly wandering down the street before officers swooped in who said they had to knock the animal down to keep the public safe.

Mr Bennetts said that after the first strike, the cow 'tried to get back up, and then they (the police) pushed it back over and blocked it by its neck and top half of his body and so it couldn't get up' - adding: 'Inhumane is all I can say.'

Shocking footage shows police brutally smashing into the calf twice after it escaped from its enclosure as a nearby member of the public shouts: 'What are you doing that for?'

Mr Cleverly was among many high profile names condemning the 'brutal' actions of the police force.

Surrey Police has said in a statement: "The cow was running loose throughout the evening on a number of main roads and during this time, we received numerous calls from the public reporting a car being damaged and it running at members of the public.

"Given these reports, officers were extremely concerned about the public’s safety, and over a period of a number of hours tried a number of options to safely capture the cow.

"Unfortunately, these were unsuccessful, and the decision was made to stop it using a police car. This matter has been referred to our Professional Standards Department. The Independent Office for Police Conduct has been notified and a voluntary referral will be made in due course."

The cow has now been moved to a nearby farm with the owner located and a vet assessing the animal's injuries - described as 'a large cut to its legs'.

Chief Insp Sam Adcock said: "I know that this has caused distress and I’d like to thank the community for their concern.

"The decision to use the police car is one that was only taken after other methods to stop the cow had failed.

"There will be an investigation into the actions that led to this, but our focus at all times is on ensuring the safety of the public.

"I know there are videos circulating of this incident, which the public may find distressing. I would ask that these videos are sent directly to us to help with our investigation."