Former News of the World editor Andy Coulson was released on Friday after he spent less than five months in prison. Coulson was sentenced to 18 months in jail, in July, after being found guilty of a conspiracy to hack private phone calls in pursuit of stories.

Coulson will reportedly have to wear an electronic device until he finishes half of his sentence under house arrest, according to an agreement for his early release, The Guardian reported. The former editor was imprisoned at Hollesley Bay, an open prison in Suffolk, about 96 miles north of London.

"Public protection is our first priority. Only prisoners who pass a strict risk assessment can be released on home detention curfew (HDC),” a spokesperson for the Ministry of Justice, said, according to BBC, adding: "Offenders on HDC are subject to strict licence conditions and can be recalled to prison if they breach them."

Coulson, 46, initially spent two months at Belmarsh prison in southeast London, before he was moved to Suffolk. His trial was widely followed around the world after it was revealed that, under his leadership, the newspaper had hacked into the phone of a murdered schoolgirl, Milly Dowler, in 2002, for a story. It was also found that the newspaper had listened in on phone calls of several other celebrities.

Coulson had denied all the charges against him but was found guilty of plotting to intercept voicemails between 2000 and 2006. Five defendants, including Rebekah Brooks, the former chief of News International, were cleared of all charges, BBC reported.

"Mr Coulson has to take the major blame for the shame of phone hacking at the News of the World. He knew about it, he encouraged it when he should have stopped it," Justice Saunders, the trial judge had said, according to The Telegraph.

News of the World announced the closure of the newspaper on July 7, 2011, and Coulson was arrested on July 8.