Sentencing, Mr Justice Fulford told April Casburn she had been guilty of "a corrupt attempt to make money out of sensitive and potentially very damaging information".
The judge went on:
Activity of this kind is deeply damaging to the administration of criminal justice in this country.
It corrodes the public's faith in the police force, it can lead to the acquittal or the failure by the authorities to prosecute individuals who have committed offences whether they are serious or otherwise.
We are entitled to expect the very highest standards of probity from our police officers, particularly those at a senior level.
It is, in my judgment, a very serious matter indeed when men or women who have all the benefits, privileges and responsibilities of public office use their position for corrupt purposes.
He said he was particularly concerned about Casburn's child, and admitted that her absence while she is in prison could be damaging.
But he said that, had she not been arrested, the detective would have returned to work by now, and therefore the child would be cared for by others anyway.
More top news
The actress seized the day and had the words "carpe diem" tattooed on her wrist as an 81st birthday gift from her daughter.
The deadline to become the next Conservative Party leader closed at midday - but who are the contenders?
The extra deployments will bring the total number of British personnel in Iraq to 1,100.