DISGRACED former No 10 spin doctor Andy Coulson was handed the "major share of the blame" for phone hacking at the News of the World as he was jailed for 18 months.

The father of three, 46, was found guilty last week of conspiring to intercept voicemails at the now-defunct Sunday tabloid after an eight-month Old Bailey trial.

Judge Mr Justice Saunders singled out the former editor for the heaviest punishment, describing the hacking of murdered schoolgirl Milly Dowler's phone as "unforgiveable".

He said: "Mr Coulson, on the jury's verdict, has to take the major share of the blame for the phone hacking at the News of the World. On the jury's verdict he knew about it and encouraged it when he should have stopped it."

On the voicemail interception in 2002 which suggested Milly Dowler might be alive, the judge said: "The News of the World delayed telling the police the contents of the voicemail until they realised that they were not going to find Milly.

"That was unforgiveable and could only, in my judgment, have happened with the knowledge of the person editing the paper that week, Andy Coulson."

He said their motive for hacking Ms Dowler's phone was to sell newspapers, not to help her, and he added that ignorance of the law was no excuse for Coulson.

Coulson's former boss David Cameronlast week apologised for hiring Coulson in 2007.

On a visit to Scotland yesterday he said after the sentence: "What it says is that it is right that justice should be done and no-one is above the law."

There was no reaction from Coulson, who arrived at court without his wife Eloise. He was flanked in the dock by three former colleagues and private detective Glenn Mulcaire, who all admitted their part in hacking before the trial started last year.

News of the World news editor Greg Miskiw, 64, from Leeds and chief reporter Neville Thurlbeck, 52, from Surrey, were each jailed for six months. News editor James Weatherup, 58, of Brentwood in Essex, was jailed for four months, suspended for 12 months, and ordered to do 200 hours unpaid community work.

The judge described Mulcaire, 43, of Sutton, south London, as "lucky", saying it would be wrong to jail him again after he served a sentence in 2006 when he was first convicted of phone hacking.

He was sentenced to six months in jail, suspended for a year, and 200 hours community work.

Mr Justice Saunders went on: "All the defendants that I have to sentence, save for Mr Mulcaire, are distinguished journalists who had no need to behave as they did to be successful.

"They all achieved a great deal without resorting to the unlawful invasion of other people's privacy. Those achievements will now count for nothing."

He criticised the journalists for not exposing what went on. "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.

"I accept that that would require great courage but the best investigative journalists have never been short of courage."

Weatherup and Mulcaire declined to comment as they left the courtroom.

According to Mulcaire's notes, Miskiw tasked him 1,500 times, Thurlbeck 261 times and Weatherup 157 times, the court heard. Mulcaire, who was paid around £500,000 by the paper, was first convicted of phone hacking with royal reporter Clive Goodman, who was told during the trial he would not face any more hacking charges.

After the fresh police investigation into hacking, Mulcaire admitted three more counts of conspiring to hack phones and a fourth of hacking the voicemail of Ms Dowler in 2002 - which eventually led to the News of the World closing in 2011.

While Coulson was in charge, the paper was hacking a host of royals, celebrities, politicians and ordinary members of the public on an industrial scale amid intense competition for exclusive stories, the trial heard.

Coulson's co-defendants Rebekah Brooks and managing editor Stuart Kuttner were cleared of all charges last week.