The unmarried Irish father of twin boys, who were taken to England by their mother without his knowledge or consent, will have them returned to Ireland next month.
Mr G is entitled to have their custody decided by the Irish courts and not in England, the High Court in London ruled yesterday.
The boys' mother will now return to Ireland with the children at the beginning of the new year.
Mr Justice Ryder endorsed a voluntary agreement reached in court yesterday between Mr G and the English mother of the three-year-old boys, Ms O, that she would return with them to Ireland for custody to be decided by the District Court.
It marks the end of a year-long first stage to the 39-year old academic's battle, invoking the Hague Convention, for legal rights to his sons.
His estranged 33-year-old former partner took the children without his consent from their shared family home in Ireland in January.
The case has become a significant one for unmarried fathers and their rights, although legal experts have said that the decisions made in the Mr G case by both the High Court and the Supreme Court are particular to the circumstances involved, and do not involve substantial new rights for unmarried fathers.
In a 62-page judgment in July, Mr Justice Liam McKechnie decreed that the two-year-old boys were habitually resident in Ireland when Mr G took a case in the Trim District Court on March 9th seeking custody rights.
Mr Justice McKechnie said Mr G should have been given "substantial rights" in relation to his children at that stage, and therefore the children's continuing presence in Britain after that date was unlawful.
Documents produced in court in Ireland described Mr G as the primary caregiver to the boys.
When mother and children return to Ireland on January 2nd, two days before custody proceedings start, it will be one year to the day since she left with them.
Last month's Supreme Court ruling did not attempt to address the question of parental rights of unmarried fathers in detail and chose instead to assert the primacy of the District Court in Ireland in custody proceedings.
After a day of negotiating back and forth between lawyers for both parents, Mr Justice Ryder, the family division liaison judge for the north of England - where the mother has been living with her children - said the court would "facilitate a return of the children to the Republic for further proceedings there".
Mr Justice Ryder said he, and earlier in the day Mrs Justice Hogg, had "considered the same facts that led to the Supreme Court decision".
The fact that both parties voluntarily agreed before the London High Court to be bound by the Supreme Court's ruling means that yesterday's decision may not be appealed and ends all English legal proceedings.
The estranged parents were in court throughout the day's submissions. Both were expressly forbidden by the judge from publicly commenting on yesterday's decision.
Outside the High Court in London, Donnacha Murphy of the organisation Unmarried Fathers of Ireland said he was happy with the ruling, but "disappointed the boys will not be with their dad for Christmas - like the children of so many unmarried fathers in Ireland".