A woman desperate to protect her three grandchildren from a predatory paedophile has won a vital round of her battle to make Islington Council recognise the risks of abuse.

The grandmother says the children, the youngest aged six, have already been “groomed” by her daughter’s sex-offender ex-boyfriend and has refused to let them leave the house alone since he was released from jail following a conviction for a sex attack on a 10-year-old boy.

She asked the council to rehouse her and the youngsters outside the borough for fear of being targeted by the paedophile – but was met with the response that she was “over-protective” and that the children were at no more risk of a sex attack than any other child in Islington.

The council even threatened to prosecute her after she kept the children out of school for fear that they would be accosted by the man, who has a string of serious child sex offences, going back more than 10 years, on his record.

But last week three Appeal Court judges handed the grandmother an important victory when they ruled that an October 2012 assessment of the risk posed by the paedophile to the children was “fundamentally flawed”.

Describing the sex offender as “a very high risk” to the youngsters, the grandmother’s barrister, Ian Wise QC, told the court that her ultimate objective was to make the council move her and the children to a secret address outside the borough where they can be safe.

However, Islington Council insisted that the grandmother’s concerns were over-blown.

Lady Justice Black said a police officer asked to report on the case had initially said that there was no real threat of the children being “snatched” by the mother’s ex-boyfriend and that there was little danger of them being targeted for abuse.

However, the same officer later performed a dramatic volte face, saying that the paedophile had a history of abusing children known to him and that no youngster who had had contact with him could be considered safe.

The judge, sitting with Lords Justice Thorpe and Longmore, said the council had failed to give that fundamental change in stance the “rigorous probing and critical evaluation” it required and its risk assessment was thus “fundamentally flawed”.

The council must now carry out a fresh risk assessment and reconsider the grandmother’s plea for her and the children to be relocated a safe distance away from Islington.