A police officer has been cleared of attacking a pro-hunt demonstrator in Parliament Square.
Pc Latteman said he was defending himself
Pc Neil Latteman, 43, told Bow Street Magistrates' Court he was protecting himself when he hit Yorkshire farmer Mark Faulkner, 34, exactly a year ago.
Pc Latteman said he had used approved police tactics to help subdue Mr Faulkner who was going "berserk".
Dismissing the case, District Judge Timothy Workman said he could not be sure the officer was acting unlawfully.
The court heard that Pc Latteman had used a police-approved technique to stun a struggling suspect with a hard blow to a cluster of nerves in the neck and face.
In notes produced hours after the incident the officer had written: "I threw one punch in his face, fearing for my safety."
Hunting with Dogs Bill
Judge Workman said: "He clearly maintained he was acting to assist the arrest and used an approved technique which he insisted were necessary in the circumstances.
"I cannot be sure that the defendant was lying when giving his evidence that he was acting lawfully in striking Mr Faulkner, therefore the case is dismissed."
The defence had claimed Mr Faulkner, from Thirsk in North Yorkshire, had been trying to incite the crowd to break police lines.
Mr Faulkner was at the front of the protest when he was hit twice by a police officer with a baton, causing him to fall and lose consciousness.
He was then pulled from the crowd for an alleged breach of peace and pushed against a police van when the incident with Pc Latteman took place.
He suffered a bruised forehead, a black eye, an injured lip and bruised elbow.
Protesters and police clashed in Parliament Square on 15 September as MPs voted on the Hunting with Dogs Bill.
Of the 1,300 officers deployed on that day, 60 were injured.
Televised scenes of bloody protesters prompted criticism of police tactics but former Metropolitan Police Commissioner Sir John Stevens defended his officers, saying "nobody got cracked over the head for no reason".