Last night, after Cullen, 85, admitted 21 offences against children as young as six, Derby North MP

Chris Williamson said of the news that he had evaded justice for 22 years: “I think it is a shocking revelation.

“Bringing him to justice earlier is an obligation you would have expected the authorities to fulfil.

“I think the victims have been badly let down in this awful case.”

Cullen abused his Derby victims while priest at Christ the King Catholic Church, Mackworth.

Church authorities, who helped in the hunt for Cullen, condemned his crimes as “wicked and abhorrent”.

It was a tip-off from a Derby churchgoer that helped snare Cullen, who had worked for 18 years in Mackworth.

He was traced to Tenerife by police after they were in turn told of his whereabouts by the Catholic church.

Yesterday, at Derby Crown Court, the 85-year-old, who was extradited back to Derby last year, pleaded guilty to 21 counts of sexual abuse – four against altar boys during his time in the city.

Shuffling into the dock in an oversize baggy sweatshirt, he looked gaunt as he admitted 15 counts of indecent assault, five of indecency with a child and one count of committing a serious sexual offence.

The offences took place between 1957, when Cullen was 28, and 1991 and involved five male victims and two females.

The two girls were abused when he worked in Buxton and the fifth boy when he worked in Nottingham.

Judge Jonathan Gosling adjourned sentencing until March 24 warning the paedophile that he faced "a lengthy prison sentence".

Cullen, who from 1960 to 1978 was the parish priest of Christ the King, in Mackworth Estate, had been arrested and charged with an offence against a Nottingham victim in 1990.

But after being bailed by the court in 1991, he failed to return.

Last night questions were being asked about how Cullen could have evaded detection for so long, including a demand for answers from Mr Williamson, who said authorities had an "obligation" to have tracked him down earlier.

The MP added: "At the same time I think the officer that worked on the case for Derbyshire police should be thanked for the diligent inquiries he undertook on behalf of these victims and the effective way he helped bring about a conviction."

Derbyshire police became involved in the investigation when a Derby victim came forward in 2005.

Officers approached the diocese to see if they could help track him down.

Father Andrew Cole is the Private Secretary to the Bishop of Nottingham, the diocese which covers Derby.

He said it was his safeguarding committee that was told Cullen was living in Tenerife.

Father Cole said: "The tip-off came from a churchgoer in Derby who told the Bishop that Cullen was living in Tenerife.

"The Bishop wrote to his counterpart Bishop in Tenerife who asked his priests if they knew who Cullen was and if he was attending their churches.

"One of them got back to that Bishop, who wrote to our Bishop and, through the safeguarding committee, we told Derbyshire police.

"We believe Cullen had failed to return to bail after an arrest and charge in 1991 and he went on the run for more than 20 years.

"Now, we are very pleased he has admitted what he has done.

"He has pleaded guilty, meaning those who he committed these abhorrent crimes against will not have to face him in court.

"What he did was absolutely wicked."

Father Cole said the Catholic Church took the safeguarding of children and vulnerable adults "extremely seriously", and it was its hope and expectation that no child or vulnerable adult should ever suffer at the hands of others.

He said the church would continue to work with police and other authorities whenever allegations of abuse arise, and would "ensure that its churches and parishes are safe and welcoming for all members of the community."

Father Cole said: "We have been working closely with the police throughout the preparation of this case, both before and after Cullen's arrest, have encouraged them to bring him to justice and are grateful to them.

"I would like to offer our sympathy to those who have been affected by this tragedy in any way and assure them that we will do whatever we can to support them.

"I also wish to thank Cullen's victims for their bravery in coming forward after many years of silence; it is due to them that Cullen has pleaded guilty and now awaits sentencing on March 24.

"Nothing can take away the horror of what happened to them, but I hope that today's verdict will help them in some small way to find peace. The abuse of children is abhorrent, by whomsoever it is perpetrated, as is any attitude of mind which somehow tolerates it."

In court yesterday, during the 20-minute hearing, each charge was put to Cullen.

Softly spoken he bowed his head and replied "guilty" to each one.

The Mackworth offences, which total 13, involved four altar boys and date between 1957 and 1974. Five offences relate to two girls who were abused between 1980 and 1985 in Buxton. The final three counts relate to one male victim in Hyson Green, Nottingham, between 1989 and 1991

Judge Gosling told Cullen: "You will know that a very substantial sentence is inevitable."

Detective Constable Matt Goodwin led the investigation for Derbyshire Police.

Speaking outside the courtroom, he said: "Derbyshire police are happy with the guilty pleas Cullen has entered.

"Obviously this has saved the victims the ordeal of having to stand in the witness box and give evidence in a trial. We would very much like to thank them for their bravery.

"It is due to them coming forward that we have seen Cullen enter those guilty pleas.

"We would also like to thank the safeguarding council at the diocese of the Catholic Church for their help in tracking down Cullen in Tenerife. Without their help and support this man would not have been brought to justice."

Councillor Paul Pegg represents Mackworth on Derby City Council. He said that although he had lived in Mackworth for most of his life he did not know Cullen.

Mr Pegg said: "I am pleased that he has admitted his crimes and spared the victims the terrible ordeal of having to face him in the courtroom during a trial.

"My thoughts are with those victims and I hope they are able to get some closure from his guilty pleas."

Nottinghamshire Police arrested and charged Cullen In September 1991 with sexual offences.

He appeared at court in October 1991 and was bailed.

A spokesman said: "He failed to return to court and the court issued a warrant for his arrest.

"In 2000, the court withdrew the warrant which effectively meant he was no longer wanted.

"In 2005, Derbyshire Police received allegations of sexual offences against Cullen and asked for details of the Nottinghamshire complainants. Nottinghamshire provided the details.

"In 2012, a further complaint was received by Derbyshire and Cullen was located. When the warrant was made we carried out checks on his last known address, employers, tax authorities, places he might sign on or visit.

"We would stop looking when the warrant is cancelled as he is no longer considered wanted."

A spokesman for the Ministry of Justice said that the court where Cullen failed to attend – Nottingham Magistrates' Court – should hold a record of who asked for the application for the warrant to be cancelled.

Nobody at Nottingham Magistrates' Court was last night available to provide that check before the Telegraph went to press.