Former News of the World editor Andy Coulson will have to wear an electronic tag after been released from prison.
The ex-Downing Street communications boss left Hollesley Bay, an open prison in Suffolk, this morning.
Coulson, 46, has served less than five months of an 18-month term imposed in July after he was found guilty of conspiring to intercept voicemails at the now-defunct Sunday tabloid following an eight-month trial at the Old Bailey.
It is understood Coulson will have to wear an electronic tag until he has served half of his full sentence as a condition of his early release.
The Ministry of Justice declined to comment on an individual prisoner but said inmates can be released under home detention arrangements before they have served half of their term.
A spokesman said: "Public protection is our first priority. Only prisoners who pass a strict risk assessment can be released on home detention curfew (HDC).
"Offenders on HDC are subject to strict licence conditions and can be recalled to prison if they breach them."
Prisoners can be considered for HDC if they are serving a sentence of more than three months and less than four years and have served a quarter of their sentence.
Coulson was previously held at HMP Belmarsh in south east London but it was reported in September that he was moved to Hollesley Bay to serve the rest of his term.