A judge is to urge the Foreign Office to help find a 12-year-old British girl who has been missing since a trip to Egypt more than seven years ago.
Elsa Salama was taken by her father Tamer Salama while she and her mother were visiting his relatives in 2011.
Her mother, Naomi Button, from Leeds, has not seen her since.
High Court judge Mr Justice Mostyn said he aimed to ask Foreign Secretary Jeremy Hunt to use all "diplomatic measures" to find her.
The BBC has asked the Foreign Office for a comment.
Elsa is at the centre of proceedings in the Family Division of the High Court in London.
Judges have heard how the Egyptian former teacher took Elsa from her mother in December 2011 while all three were visiting his relatives in Egypt.
Ms Button, a leadership consultant from Leeds, was forced to return to England alone.
She then launched legal action in the hope of getting Elsa home.
Salama, who subsequently returned to England without Elsa, was jailed in January 2012 for breaching judges' orders to arrange Elsa's return to England or to reveal where she was.
But a judge ordered his release in December 2013 after deciding that continuing to keep him in prison was no longer proportionate or justifiable.
Mr Justice Mostyn said at a High Court hearing on Wednesday he thought a formal approach to Mr Hunt should be made.
"I intend to write a judgment respectfully pleading with the Foreign Office to use all diplomatic measures to locate this British child... who has been missing for all these years," he said.
"Although there have been informal approaches to diplomatic sources, there hasn't yet been a formal approach made."
A judge has already made Elsa a ward of court - a move which gives judges the power to make decisions about a child's movements.
Salama, who lives in Manchester, has told judges that Elsa is living with his mother in Cairo and beyond his control.
A judge overseeing the case six years ago described Salama as "shifty, evasive and plainly dishonest" and said his behaviour was "cruel beyond imagination".
Mr Justice Roderick Wood said at a hearing in 2013 he had no doubt that Salama could "cause" Elsa's return "should he wish to do so".