PC Kenneth Wilson, of Newton-le-Willows, told Manchester Crown Court last week that he only restrained the girls to stop them attacking him and his colleagues and to ensure they were searched properly.

PC Wilson, who denies misconduct in public office, said one of the alleged victims, Jamie Lee Hall, then 18, had been "volatile" and had threatened him and his colleague PC Kerry Williams while in the back of a police van.

Miss Hall and her friend Amy Keigher, who was also 18, had been arrested after an unprovoked attack on two women leaving a fancy dress party in Manchester city centre in October 2008.

The jury was told that PC Wilson had arrested Miss Hall and Miss Keigher earlier that year after an incident in which a shopkeeper was racially abused, had his premises damaged, and was stolen from.

Speaking of the night he restrained the two girls at the station, PC Wilson said the fact they had attacked "two random people" meant he had "got to consider they had a possible violent tendency".

Explaining why he used an armbar on Miss Hall in the custody area of the station, PC Wilson, 41, said: "In custody you don't even have five seconds to make a decision."

He added that the armbar had stopped her from striking out, spitting, headbutting or kicking while she was searched.

He said that tensing in her arm and the "resentment" in her face led him to believe she could injure somebody.

PC Wilson claimed Miss Keigher had become agitated in the custody area and said he had put his hand on Miss Keigher's neck because she began shaking her head back and forth violently.

He said another option would have involved "taking her to the ground", but he had not wanted her to be injured.

The court heard PC Wilson had previously been smashed in the face with a detainee's elbow, headbutted, kicked and punched on the job.

PCs Kerry Williams, 24, and Jason Hanvey, 37, civilian detention officer Kristina Hawkins, 36, and Sgt Andrew Kennedy, 51, also deny misconduct in public office.

(Proceeding)