A POLICE chief has hit back at "untrue" claims that a convicted child rapist paid to help snare a paedophile gang was placed "in the midst" of vulnerable women and girls.

Northumbria Police Chief Constable Steve Ashman was responding to a storm of criticism from child protection groups after it emerged that the force paid a man, known only as XY nearly £10,000 over 21 months to find out about the times and whereabouts of parties where girls were being plied with drugs and alcohol.

An "appalled" NSPCC raised questions over the force's approach to child sexual exploitation cases after it emerged during a pre-trial hearing.

Mr Ashman accepted officers faced a "moral dilemma" over the cash paid to the sex offender in helping secure convictions.

A total of 17 men and one woman were convicted of or admitted charges including rape, supplying drugs and inciting prostitution, in a series of trials at Newcastle Crown Court.

Mr Ashman said: "It's quite surprising and disappointing for the NSPCC in particular to adopt the stance they have.

"This is an ill-informed position that they've taken. The fact of the matter is we absolutely did not plant XY, the informant, in the midst of vulnerable women and girls.

"Not only did we not ask him to do it, there's no evidence whatsoever that he was engaged in offending against these victims or anybody else."

He said use of XY was to find who the suspects were, their addresses, and what criminal behaviour they were involved in.

He said: "I absolutely understand that this is challenging for some people but I'm left with a question that I throw back – not to be clever or to evade the issue – what would you do in those circumstances?

"Would you take that risk under carefully managed circumstances, that doesn't expose him to vulnerable women and girls? Is that the right thing to do? Morally does that weigh up? To me, it does.

"Some people might disagree with that, I get that – it's a problem that we wrestle with ourselves – but I've got to be content on the back of 93 convictions, over 300 years of imprisonment, without the verdicts that we received yesterday, this was the right thing to do overall."

Asked whether the informant was necessary to gain convictions, he said: "You might have got that evidence through other means but it might have taken a whole lot longer and that in itself would have exposed vulnerable women and girls - given the scale of this - to an unacceptable level of risk, and personally that doesn't sit comfortably morally with me either."

Jim Gamble, who set up the Government's taskforce to fight child sexual exploitation, criticised the police move.

He told the BBC: "I think all police forces are under pressure to get things right.

"But there are ways and means to doing it ... there need to be limits and there should be lines that shouldn't be crossed.

"In my opinion they have gone way over the line on this one.

"Personally, I can't envisage any circumstances where I would have authorised payment to someone convicted of rape.

"I can't imagine how you could have control mechanisms in place with an informant of that type ... that would give you reassurance that they didn't still represent a risk to young and vulnerable women, given what I know about this person's history."

A total of 461 people have been arrested as part of the investigation, while 782 potential complainants have been spoken to and 278 victims found.

Nazir Afzal, the former chief prosecutor in Greater Manchester who oversaw the Rochdale case, said he also had reservations about the Northumbria Police investigation.

He told BBC Breakfast: "You can use - and should use - informants when you're tackling organised crime because they have credibility.

"But when it comes to child sexual abuse, I've prosecuted offenders in their 70s and 80s - they don't change their behaviour invariably.

"Putting predators with other predators in the company of their prey is really dangerous - and I can't think how you could manage that risk."

However, a charity working with victims said the number of successful prosecutions meant paying XY was justified.

The investigation, Operation Shelter, was part of Operation Sanctuary, a long-running Northumbria Police probe in the area.

Stephen Bell, chief executive of Changing Lives, said the organisation had worked with 33 Sanctuary victims and 16 related to Shelter.

The charity has helped them go through the court process, will work with them on rebuilding their emotional strength and support them back into society with training or education.

Mr Bell said many of the victims did not trust authority figures, but Northumbria Police had worked hard on presenting them with a "friendly face" to build relationships.

Regarding the use of XY, he said: "I am pleased I did not have to take that decision."

He said it was recognised that few sex crimes are prosecuted and even fewer lead to convictions.

"To have 18 out of 25 (Operation Shelter defendants) prosecuted and convicted and taken off the streets is a huge percentage," he said.

"Therefore you can argue that the ends justify the means.

"We know that a number of people would not have been jailed without this information.

"I understand it is very emotive."