what about the thousands of successful interventions that do not get publicised?
Or of course, the thousands of 'UNSUCCESFUL' interventions that do not get publicised..
The law may not be on their side, depending on which part of the law of course, but do not underestimate the power they wield when making their innacurate, and poorly punctuated reports to the family courts, punctuations that can totally turn what was said or meant, completely on it's head..
When it was alleged and supported by a consultant paedeatrician that my ex was beating my son, social services accepted her reason and took no action, as the court case moved along and each reason for his injuries was challenged, social services accepted the further FIVE reasons given for his injuries, until the extremely wise and experienced judge called her a 'liar'... Social services ?? ' HAH' !.. 
I can sympathise Jusme with your point of view having seen at close quarters how Social Services in Kent operate. They have recently been judged to be the worst performing Social Services in the UK!
In fact within Kent Police social services are renowned to be a "law unto themselves" (a quote from a senior police officer I was speaking to). To reinforce this I personally know of a lady who lost a child to care due, in the official words of a Kent judge, and recorded in an official court document I have seen, 8 counts of Social Services committing illegal acts.
No doubt there are many good SS workers, and I have met some of them, but their power often corrupts and they do not always act in the interests of both the parents and child, especially with "soft target" cases. In the case of a "hard target" which I can quote in fact they took far too long to take any action at all to take children into care who were living in terrible conditions.
They have just got to improve their performance, and now Kent County Council are taking the necessary steps to resolve this.