A thug who was jailed after he subjected a woman police officer in Carlisle to a brutal attack has been freed - after serving only a quarter of his 10-month sentence.

PC Diane Irving suffered facial bruising so severe she was barely recognisable.

While on patrol in Botchergate, Carlisle, on December 27 last year, she spotted 24-year-old Kieron Murray collapsed in the street and went to help him. He responded by punching her hard in the face.

Murray, from Esk Road, Lowry Hill, Carlisle - was jailed at Carlisle Crown Court on September 7 after the judge heard how he taunted the officers who arrested him with references to Dale Cregan, who murdered two female police officers.

Passing sentence, Judge Peter Davies told Murray: “Police in this county are going to be protected, and protected by me, from thugs like you.”

The News & Star has confirmed that Murray was released from jail on November 22 - just 76 days into his sentence. His release conditions include a 3pm to 7am curfew at his family’s Lowry Hill address.

“It’s a disgrace,” said Martin Plummer, chairman of Cumbria’s Police Federation, which represents rank and file officers.

“Given the circumstances, we felt the original sentence was lenient. At the time Diane was not too disappointed: she knew he’d at least be spending Christmas in prison. Now we know he’s home for Christmas.

“For her to find out he was released on November 22 was a huge shock. To say she was upset, disappointed, and deflated is an understatement. When Murray attacked her, Diane was in uniform, and going to his aid.

“He jumped up and hit her hard in the face.

“The doctors suspected she had fractures to her cheekbone and her eye-socket, but the swelling was so intense they couldn’t confirm that. Diane is a strong woman, but after this she was in bits.

“We’re not looking for an increase in his sentence, just for it to fit the crime.

“Police officers put themselves in harm’s way to protect the public and expect the judicial system to support them. We need to send a clear message: that if you assault or abuse a police officer... you’ll pay the price.”

“I feel desperately sorry for Diane.”

Carlisle MP John Stevenson said: “It’s appalling. As members of the public, we all benefit from the hard work and dedication of front line emergency service workers.

“In return, they expect the judicial system to support them.”

A HM Prison and Probation Service spokesman said: “No one is released from prison without a tough risk-assessment, close monitoring, and strict licence conditions which if breached can lead to more time behind bars.”

Home detention curfews, for prisoners serving between 12 weeks and four years, are possible if the prisoner has served a quarter of the jail term.

A new law recently doubled the maximum sentence for common assaults on emergency workers to 12 months.

n Murray admitted assault causing actual bodily harm.