VULNERABLE Becky, 17, lives with heroin addict Mike, 22. She has been subjected to abuse in her past and could go back on the at-risk register if she lost his support.

Social services know all about Mike's problem - he recently escaped a prison sentence for possession of the class A drug.

But he is Becky's "designated carer" and his solicitor persuaded Blandford magistrates to let him stay in the community - partly for Becky's sake.

Jason is a toddler whose parents are both heroin addicts and convicted drug dealers. His "designated carer" is a grandparent who also has convictions relating to drugs.

Another young woman who recently appeared before the Central Dorset Bench is the carer for her pregnant 16-year-old sister.

Dorset Social Services chiefs are aware of the background in all these cases and of many other similarly desperate situations.

But social workers resist the public demands to take children out of drug dens or vulnerable young people away from new family groupings, however unconventional.

Social services boss David Joannides said it was not possible to provide ideal solutions.

"Our job is to undertake risk assessment and provide the safe environment that we think is achievable," he said.

"We make assessments about whether somebody who is a drug user is capable of providing a safe environment for a young person.

"In the case of a 17-year-old we can't simply impose our view on them. We have to negotiate and take their views into account."

Mr Joannides said if Becky were forcibly removed she might be exposed to higher levels of risk. She could run away and end up on the streets.

"Nobody would want Mike to be a drug user but he may be capable of keeping it to himself ," he said.

"There are addicts who are into pushing and dealing, who revel in others around them using drugs. But for some addicts the last thing in the world that they would want is others to become embroiled."

And although young children may benefit from being placed in a foster family Becky was unlikely to benefit.

"It's quite likely that young people in her situation have lost their faith in their families to protect them. If they have found a family where they feel safe - even though we may have reservations - they put down roots and develop relationships and if they do not become subject to drug abuse, we wouldn't want to break that."

Mr Joannides acknowledged that the public wanted children like Jason to be removed to a place of safety.

The system would collapse if every child of every drug user were taken into care, he said.

Abused children certainly are taken into care, but the little ones of drug users are likely to be on the at-risk register, under close scrutiny.

"There are some families we're supervising where the parents have been convicted of the most heinous offences but there is no evidence they are any danger to their own children," said Mr Joannides.

"With the right level of support and supervision parents can be helped to maintain children within their own family.

"Many parents are trying to kick the habit or working very hard to minimise the impact of that on themselves and others. If we remove that child would we actually be creating a better chance, a better living environment?

"Cases like this are likely to be ever more subject to challenge because the child's human rights are being affected by us intervening or not intervening."

Social workers liaise closely with GPs, health visitors and playgroups to see if the child is thriving.

"We would look at distressed behaviour, neglect, not reaching their milestones," he said.

"If you didn't have all that and went to court it would be thrown out. Unlike the public, we're not allowed to make judgements about people like Jason's grandfather."

* Although Becky, Mike and Jason are real people, their names have been changed.