Twenty-one people have now been convicted after the biggest investigation by West Midlands Police into child sexual abuse in the force’s history.

The crimes by a “network of child abusers” took place against seven victims, who were aged 12 and younger, spanning a period of nearly a decade in Walsall and Wolverhampton.

Prosecutors said the offenders carried out “the most appalling catalogue of sexual abuse of the utmost gravity” which caused their victims “physical harm and extreme psychological harm”.

A police officer involved in the investigation said the “systematic” abuse was “some of the most shocking I have seen in my career”.

The offences were uncovered by Operation Satchel after concerns were raised when one of the victims went to hospital with a suspicious injury.

The third and final of three trials has now concluded, with a total of 13 people jailed and four other people due to be sentenced.

Prison terms ranged from life to 28 months, while four of those convicted received non-custodial terms.

In the first trial, which ended last May, among those convicted was James Evans, 38, who was jailed for life with a minimum term of 18 years after being found guilty of 20 child sexual abuse offences.

Also, 34-year-old Mark Smith was sentenced to 19 years behind bars with an extended licence period of six years after being found guilty of four child sex abuse offences.

In the second trial, which concluded in February this year, nine people were convicted including Tracey Baker, 41, who was jailed for 16 years for five child sex abuse offences.

Also, 41-year-old David Baker was sentenced to 21 years in jail, including one year on licence, for seven child sex abuse offences.

In the third trial, which has just ended, Matthew Evans, 32, John Griffiths, 66, and Violet Griffiths, 66, were found guilty of multiple child sexual abuse offences at Wolverhampton Crown Court. They will be sentenced next month.

Detective Chief Superintendent Paul Drover said a large team of officers investigated the allegations for more than half a decade, uncovering “systematic abuse that has to be some of the most shocking I have seen in my career”.

Joanne Jakymec, chief crown prosecutor, said: “The offenders in this case perpetrated the most appalling catalogue of sexual abuse of the utmost gravity causing the victims physical harm and extreme psychological harm.

“With the exception of one of the offenders who admitted what they had done, none of the rest have shown the slightest remorse.”

She praised the “bravery” of victims and witnesses, adding “without their support it would not have been possible for the prosecution team to convict this large network of child abusers”.

Trial one:

James Evans, 38, who was jailed for life with a minimum term of 18 years and given an indefinite sexual harm prevention order (SHPO) after being found guilty of 20 child sex offences

Kirsty Webb, 36, who was jailed for 10 years, given an indefinite restraining order in respect of the victims and a 30-year SHPO after being found guilty of five child sex offences

Mark Smith, 34, jailed for 19 years with an extended licence period of six years, making a total of 25 years, for four child sex offences. He was also handed an SHPO for 30 years and an indefinite restraining order in respect of the victims

Pamela Howells, 58, was jailed for seven years for three child sex offences and was also handed an SHPO for 15 years and an indefinite restraining order

Lee Webb, 40, was found guilty of three child sex offences and was jailed for six years with a 30-year SHPO and an indefinite restraining order

Ann Marie Clare, 43, was jailed for eight years for four child sex offences, with an extended licence period of three years for 11 years in total. She was also handed an SHPO for 30 years and an indefinite restraining order

Dean Webb, 35, was found not fit to plea but a jury decided he had committed the acts alleged. He was given a two-year supervision order and a 40-year SHPO

Stephen Webb, 65, was also found not fit to plea but the jury decided he had committed the acts alleged. He was given an absolute discharge for health reasons

Natasha Webb, 37, is due to be sentenced at a later date. She gave evidence for the Crown at all three trials.

Trial two:

Tracey Baker, 41, was found guilty of five child sex abuse offences and sentenced to 16 years in prison and given an SHPO and a restraining order, both until further notice

David Baker, 41, was found guilty of seven child sex offences and sentenced to 21 years imprisonment including one year on licence, as well as an indefinite SHPO and an indefinite restraining order

Luke Baker, 22, was jailed for two years and four months for two child sex offences and was also handed a restraining order until further notice and a 15-year SHPO

David Evans, 72, was jailed for three-and-a-half years for two offences and given indefinite restraining and SHPO orders

Jane Evans, 71, was found unfit to plea but a jury decided she committed the acts alleged. She was sentenced to a supervision order and a SHPO

Philip Wellington, 50, was found guilty of three child sex offences and jailed for nine years and given an SHPO and a restraining order, both to last until further orders

Natalie Wellington, 44, was convicted of four child sex offences and jailed for 17 years including an extra year on extended licence, alongside an indefinite restraining order and indefinite SHPO

Jason Evans, 25, was found guilty of three offences and sentenced to two years and six months, a restraining order until further notice and a 15-year SHPO

Ryan Evans, 23, was found guilty of one child sex offence and sentenced to a three-year community order, a restraining order and a 15-year SHPO.

Trial three:

Matthew Evans, 32, was found guilty of two child sex offences

John Griffiths, 66, was found guilty of two child sex offences

Violet Griffiths, 66, was convicted of two child sex offences.