One journalist hacked phones of 100 celebrities every day for 18 months, says barrister acting for victims including Sadie Frost and Paul Gascoigne

The “industrial scale” of phone hacking at the Daily Mirror, Sunday Mirror and the People made the News of the World look like a “small cottage industry” in comparison, the high court in London has heard.

Scores of celebrities, including the actor Sadie Frost and ex-footballer Paul Gascoigne, were targeted thousands of times by journalists using the illegal practice from mid-1999 until 2009, it was claimed.

In the first hint of the true extent of phone hacking at the three titles, the court heard that the former Sunday Mirror journalist Dan Evans hacked about 100 celebrities every day from 2003 to mid-2004.

Such was the reliance on phone hacking for stories that one senior journalist was desperate for Evans to create “an enigma-type machine that would automatically crack pin codes”, the court was told.

David Sherborne, the barrister for eight victims, said hacking at the titles was “utterly unprecedented” and that knowledge of the activity went to the highest levels of the newspaper group.

“This was not just the work of junior reporters … quite the opposite,” he said. “The evidence demonstrates that voicemail interception, as well as the unlawful obtaining of personal information by blagging or use of private investigators, was in widespread and habitual use by a large number of journalists across all three MGN titles.”

Between June 2002 and mid-2006, Sherborne said MGN journalists made nearly 10,000 calls to Orange’s voicemail platform, which allows people to access their messages by calling a general number and entering their personal details. He said senior MGN journalists gave “deliberately crafted and disingenuous statements” to the Leveson inquiry into press ethics, and accused MGN of withholding key evidence that meant that only the “very tip of the proverbial iceberg” could be revealed.

Two senior journalists, who cannot be named for legal reasons, allegedly introduced Evans to phone hacking in April 2003 and ordered him to build a “phone-hacking database” using pay-as-you-go phones and a list of celebrity mobile numbers. Evans, who later pleaded guilty to phone hacking, covered up his illegal activities by throwing his mobile phones – dubbed “burners” – into the river Thames every two months, the court heard.

The evidence came on the opening day of a civil trial brought by eight claimants – including Frost, Gascoigne and BBC creative director Alan Yentob – against MGN for invasion of privacy.

The judge, Mr Justice Mann, is being asked to assess the extent of phone hacking across the three titles and rule on the level of damages for each of the claimants. The other claimants involved in the case are TV soap stars Lucy Taggart, Shane Richie and Shobna Gulati, flight attendant Lauren Alcorn and TV producer Robert Ashworth.

Frost is alleged to have been hacked on a daily basis, morning and evening, in part because she was married to fellow actor Jude Law and was good friends with the model Kate Moss.

She described having her voicemails intercepted as like being “monitored and hunted down by a sort of secret police, who were digging into our lives as much as they could in order to discover every possible detail about our private lives, as well as our professional ones, to use against us”.

Sherborne said the “most deeply private” information was intercepted and published by journalists, including Frost’s attendance at AA meetings, Richie’s financial problems, Ashworth’s divorce, and Taggart’s relationship with actor Steve McFadden.

Of the stories that Mirror Group has admitted were the result of phone hacking, 49 were printed in the Sunday Mirror, 40 in the Daily Mirror and 23 in the People between June 2000 and October 2006.

“Strangers were deliberately picking through this, sifting for things they could get away with publishing,” Sherborne said. “No one imagined that all this private information, this treasure trove about just the sort of people who filled these newspapers in their millions, could be accessed and listened to in this way, let alone plundered as a source for stories.”

Frost, for example, was hacked at least twice daily by Evans because, like Yentob, she was deemed a particularly fruitful source of stories and was on his so-called “back pocket list” of targets. In Frost’s case, this hacking resulted in 27 articles that Mirror Group has admitted were gleaned unlawfully from her private messages.

By comparison, Sienna Miller received £100,000 in damages from the News of the World publisher in 2011 over 11 articles based on hacking by that newspaper.

MGN has admitted that 99 articles relating to the eight celebrities would not have been published without phones being hacked, the court heard.

Landline call records show that Yentob had his voicemails intercepted 330 times from July 2002 to March 2005, although the court heard that the true extent was likely to be much greater when hacking from pay-as-you-go phones was included.

James Hipwell, a former Daily Mirror journalist, said Yentob was a principal target of showbusiness journalists and that his voicemails would be used in hacking tutorials. Journalists would sing an amended version of a Spike Milligan song while eavesdropping on his messages, Hipwell claimed. In a witness statement, the BBC executive said he felt “violated on a truly massive scale” by the hacking.

Sherborne said: “It is abundantly clear that the documentary evidence before the court is only likely to reveal a tiny proportion of the total wrongdoing committed by MGN as against each of the claimants – merely the very tip of the proverbial iceberg.”

Lawyers for the victims pieced together a picture of hacking at Mirror Group using evidence including landline call data, expenses receipts for pay-as-you-go telephones, internal emails from the Sunday Mirror and the People and witness statements from former exployees including Evans and ex-reporters James Hipwell and David Brown.

Evans, who will give evidence as a witness in the trial, was allegedly instructed not to refer to telephones or voicemails explicitly in emails. Instead, he used the euphemism “getting the muppets” to stand up a story.

In one email read to court, a Sunday Mirror journalist told his bosses that an unnamed celebrity “sounds so cute on the voicemail”. In another email, a senior editorial staff member warned colleagues not to telephone a TV producer because “he’s answering” – meaning the journalists would not be able to access his voicemails and may be rumbled.

The court also heard that senior journalists made in-jokes about a hacked voicemail alleged to have been the source of a scoop revealing Sven-Göran Eriksson’s affair with Ulrika Jonsson.

In Mirror Group’s written defence statement, Matthew Nicklin QC said the group had published a public apology and had written privately to the eight victims before the start of this trial. However, he said the discovery of hacking could not be said to have caused the victims serious long-term, life-changing suffering like that in personal injury cases. Nor could their hurt be equated with the kind of traumatic lengthy bullying suffered in harassment or discrimination cases.

The publicly listed publisher had strenuously denied any wrongdoing until September last year, when it made limited admissions in court. The newspaper group has since set up a £12m compensation fund for hacking victims and last month printed an apology in its three papers for “an unwarranted and unacceptable intrusion into people’s private lives”.