Twenty members of a “vile and wicked” grooming gang have been convicted of trafficking, drugging and raping vulnerable girls in a harrowing campaign of abuse across West Yorkshire.

It can now be reported that the ringleader of the group, 35-year-old Amere Singh Dhaliwal, was jailed for life to serve a minimum of 18 years after being found guilty of 54 offences, including countless rapes of children.

Judge Geoffrey Marson QC said the crimes against 15 girls far exceeded anything he had previously seen. The gang’s “persistent and prolonged” offending, he said, was “at the top of the scale” of severity.

Details of the case, believed to be Britain’s single biggest grooming prosecution, can be disclosed after a judge agreed to lift reporting restrictions on Friday, following a legal challenge by media groups including the Guardian. One of the trials had previously almost collapsed when the anti-Islam activist Tommy Robinson filmed defendants in a live Facebook video outside Leeds crown court.

Top row left to right: Amere Singh Dhaliwal (Pretos), Irfan Ahmed (Finny), Zahid Hassan (Little Manny), Mohammed Kammer (Kammy), Raj Singh Barsran (Raj). Bottom row left to right: Mohammed Rizwan Aslam (Big Riz), Abdul Rehman (Beastie), Nahman Mohammed (Dracula), Mansoor Akhtar, (Boy) and Mohammed Irfraz, (Faj). Photograph: West Yorkshire police/PA

Jurors in the three trials heard how the men, mostly from Huddersfield, plied girls as young as 11 with alcohol and drugs before sexually abusing them in car parks, hotels, takeaways, snooker halls, on moors and by reservoirs across the region.

Fifteen severely vulnerable girls fell victim to the gang between 2004 and 2011. One girl, aged 11 or 12 at the time, was abducted from a care home and supplied ecstasy before being made to perform sex acts, Leeds crown court heard.

Many of the victims described how they were plied with drink and drugs at house parties then raped “one by one” by the men, who used plastic bags as condoms.

Dhaliwal was at the heart of the group, who referred to each other using nicknames including “Dracula,” “Beastie” and “Chiller” in monikers that were used in the three trials.

The court heard the married father-of-two committed countless rapes, incited child prostitution, trafficked girls across the region and filmed their abuse on his mobile phone.

Top row left to right: Nasarat Hussain (Nurse), Sajid Hussain (Fish), Faisal Nadeem (Chiller), Mohammed Azeem (Mosabella), Wiqas Mahmud (Vic). Bottom row left to right: Manzoor Hassan (Big Manny), Niaz Ahmed (Shaq), Mohammed Imran Ibrar (Bully), Asif Bashir (Junior) and Mohammed Akram (Kid). Photograph: West Yorkshire police/PA

His treatment of the girls was “inhuman,” the judge said, including one occasion when he sexually abused a girl with a drinks bottle during a truth or dare game. At another time, an intoxicated 15-year-old girl was raped by a man in a “dare” by Dhaliwal, while others watched. It was “degrading and wicked,” the judge said.

The girls were deliberately targeted for their vulnerabilities. All had troubled home lives, including one whose mother was unable to care for her due to drink and drug addictions.

Two of the girls had mild learning disabilities. At least one girl attempted suicide and another had an abortion, jurors heard. One of the girls was thrown out of a moving car outside her home. She had bruises all over her face and was under the influence of alcohol and drugs.

They were made to feel special by flattery, going to parties, having rides in cars and given presents, the judge said. Many thought the men were showing them genuine affection.

“What in fact was happening was that a relationship of trust was created,” the judge said, albeit that it was “entirely false and had been deliberately created to enable predatory men to perpetrate gross sexual abuse for your own perverted gratification”.

In sentencing, Marson said the victims and their families remained “profoundly affected” by their ordeal and that it was “likely that many, if not all, of these girls will never recover from the abuse they suffered”.

“I have read the victims’ personal statements; they make harrowing reading. The way you treated these girls defies understanding; this abuse was vile and wicked,” the judge said.

“As cases of sexual abuse with which the courts have to deal, this case comes at the top of the scale. None of you has expressed any remorse for what you did.”

He added: “Amongst the aggravating factors are that these girls were young when the abuse started, they were targeted because of their extreme vulnerability. They were threatened and intimidated and plied with drink and drugs often to insensibility and often in order to facilitate sexual abuse. These were planned offences by a large group of Asian men.”

Reporting restrictions, which were imposed in November 2017, were partially lifted on Friday to allow the media to report some details from the three trials.

Robinson’s Facebook video, which was viewed hundreds of thousands of times, led to the EDL founder being jailed for contempt of court in a ruling that was later quashed. He will be retried by a judge at the Old Bailey in a fresh hearing on Tuesday.

DCI Ian Mottershaw, from West Yorkshire police, paid tribute to the victims for their courage and tenacity. Speaking outside court, he said the “depraved individuals” had subjected young children to “unthinkable sexual and physical abuse” and he urged other victims of child sexual exploitation to come forward.

The 20 men convicted were:

• Amere Singh Dhaliwal, 35, of Huddersfield - jailed for life, minimum of 18 years

• Irfan Ahmed, 34, of Huddersfield - jailed for eight years

• Zahid Hassan, 29, of Huddersfield - jailed for 18 years

• Mohammed Kammer, 34, of Huddersfield - jailed for 16 years

• Mohammed Rizwan Aslam, 31, of Dewsbury - jailed for 15 years

• Abdul Rehman, 31, of Sheffield - jailed for 16 years

• Raj Singh Barsran, 34, of Huddersfield - jailed for 17 years

• Nahman Mohammed, 32, of Huddersfield - jailed for 15 years

• Mansoor Akhtar, 27, of Huddersfield - jailed for eight years

• Wiqas Mahmud, 38, of Huddersfield - jailed for 15 years

• Nasarat Hussain, 30, of Huddersfield - jailed for 17 years

• Sajid Hussain, 33, of Huddersfield - jailed for 17 years

• Mohammed Irfraz, 30, of Huddersfield - jailed for six years

• Faisal Nadeem, 32, of Huddersfield - jailed for 12 years

• Mohammed Azeem, 33, of Bradford - jailed for 18 years

• Manzoor Hassan, 38, of Huddersfield - jailed for five years

• Niaz Ahmed, 54, of Huddersfield - to be sentenced on 1 November

• Mohammed Imran Ibrar, 34, of Huddersfield - to be sentenced on 1 November

• Asif Bashir, 33, of Huddersfield - to be sentenced on 1 November

• Mohammed Akram, 33, of Huddersfield - to be sentenced on 1 November

• This article was amended on 22 October 2018 to remove personal details.