Andy Coulson, former confidant of and advisor to the British prime minister, has been sentenced to 18 months in prison for phone hacking.
Coulson, denied sanctioning hacking as editor of The News of The World (NoTW) all through his eight-month trial but was convicted by the jury.
At the sentencing today, Mr Justice Saunders said the hacking of murdered teenager Milly Dowler's phone was "unforgivable".
David Cameron said his old friend's sentence showed that "no-one is above the law".
Asked about the outcome on a visit to Scotland, Cameron said: "Well, what it says is that it is right that justice should be done and no one is above the law, which is what I have always said."
Coulson, who was David Cameron's spin doctor until 2011, saw his former boss and love Rebekah Brooks acquitted of the same charge.
He arrived at court without his wife, Eloise.
His former NoTW colleagues Nevile Thurlbeck, James Weatherup and Greg Miskiw were also sentenced along with private investigator Glenn Mulcaire. They had all admitted the offence before the trial began.
Coulson can expected to be released on licence halfway through his sentence after nine months. He could be released even earlier, if he is permitted to given a home detention curfew, where an electronic tag would confine him to his house.
Miskiw and Thurlbeck were each sentenced to six months in jail.
Weatherup was jailed for four months, suspended for 12 months, and ordered to do 200 hours unpaid community work.
Mulcaire was jailed for six months, suspended for 12 months, and ordered to do 200 hours unpaid community work.
The judge told the defendants: "I do not accept ignorance of the law provides any mitigation.
"The laws of protection are given to the rich, famous and powerful as to all."
The judge said Coulson clearly thought it was necessary to use phone hacking to maintain the newspaper's "competitive edge".
And he said the delay in the NoTW telling police about the Milly Dowler voicemail in 2002 showed the motivation was to "take credit for finding her" and sell the maximum number of newspapers.
The judge said: "Mr Coulson has to take the major shame for the blame of phone hacking at the NoTW. He knew about it, he encouraged it when he should have stopped it."
He added: "There is a certain irony in seeing men who pride themselves on being distinguished investigative journalists, who have shed light in dark corners and forced others to reveal the truth, being unprepared to do the same for their own profession."
There was no reaction from Coulson as he was jailed.
Weatherup and Mulcaire both declined to comment as they left the courtroom.
The sentencings bring to an end one of the longest and most complicated trials in English legal history and a scandal that continues to reverberate across the press and Westminster.
Campaigners said the conclusion of the hacking trial was the inevitable consequence of a "colossal failure" which allowed criminal activities to "fester for many years" at the News of the World.
A spokesman for press reform group Hacked Off said: "No-one can take any pleasure from the sentences handed down today on News of the World journalists.
"But these sentences are the inevitable outcome of a colossal failure of corporate governance within News International that allowed a culture of criminal behaviour to fester for many years.
"It has taken far too long for the thousands of innocent victims of this industrial-scale criminal conspiracy to see its perpetrators brought to justice.
"It is only the beginning of the process. Those victims will insist that no stone is left unturned to get to the full truth of what happened - no matter how high up the scandal went."
He continued: "We now need a proper independent and effective press regulator that actually works for victims and the public in preventing this sort of institutional disregard for the rights of others."